Wednesday, 22 October 2014

DNA-The Molecular Profile of a Criminal

I studied forensic sciences for nine months in one of the world’s finest forensic sciences laboratories in the early 1970s as part of my criminology training at the University of Toronto. This didn’t make me an expert on DNA but it did educate me on DNA and its uses.

Convicting a criminal without an eyewitness has always been chancy and sometimes convicting someone on the testimony of an eyewitness has been even more risky.  In 1903, when fingerprinting was first recognized in the United States, it was recognized as  being  an infallible way to get a conviction because the ridge arrangement on every finger is unique in the sense that no two persons have ever had the same fingerprints.

But many rapists and murderers didn't leave identifiable fingerprints on their victim’s bodies so detection became almost impossible. Then along came laser fingerprinting and the prints of the assailants were detected on skin, and that helped convict some, but not all.

But  if  these  criminals  didn't  leave  their  fingerprints behind, almost all of them left their semen inside the bodies of their victims. A large number of these criminals were convicted on the testimony of forensic scientists who were able to testify as to whether or not the blood type detected in the semen was the same as that of the accused.  But detecting criminals this way  was  not  always  a  sure  thing  because  20  percent  of the human population are not secreters.  A secreter is someone whose blood type can be determined by analyzing that person's body fluids-such as his semen. 
Human blood falls into four main types. They are, O, A, B and AB. The breakdown between the four are best explained this way:  Out of every 18 persons in Canada, 8 are blood type O (obviously the most common) 7 are blood type A, (a close second) 2 are blood type B and only 1 is blood type AB.

Just suppose that in North Sidney, Nova Scotia,  a small city of 7500, a man raped and murdered a woman and left his semen behind. The investigators could narrow down the suspects in the following manner.  First, they could rule out the females. That would cut the odds down to 3700 male suspects. Then they could rule out the boys under 16 and men over 65.  That would reduce the odds to 1800. And let's suppose that the murderer was a secreter and his blood type was AB. That would leave 100 possible suspects. And suppose 90 of them had an alibi that was satisfactory. That would leave 10 suspects in which one of them probably  raped and killed the woman. I used the word probably  because up to recently, all the police would have at this point in their investigation would be scientific proof that any one of the 10 suspects could  have  committed the crime, but could have  is  not  enough  to  secure  a  conviction. 

And  suppose  her estranged  boyfriend  had  blood  type AB and he couldn't account for  his  whereabouts  on  the  evening  in  question.  Would  that narrow it down to one?  It would certainly be good odds that he was the murderer but if that was the only evidence the police had, those odds of 1 out of 10 is hardly the kinds of odds a jury would want to convict someone on.
DNA identity has arrived and it is a method in which the identity of a rapist who leaves his semen inside his victim, can be determined with as little as a 1 in 30 billion to 4.5 trillion chance ever  being  wrong.  When  you  realize  that  ever  since the beginning of time, there has been no more than 78 billion people on this earth, you can really appreciate these odds. To  understand  this  highly  complex  method  of  analyzing  the suspect's semen to the nth degree, one must first understand what DNA really is.
DNA abbreviates the word, 'deoxyribonucleic acid' and is the cell substance in each of our individual cells that acts as a blueprint for our individual genetic information. Each one of our cells has exactly the same DNA in it so that the DNA in a cell taken from our hair or bone, is no different than that taken from our blood, or in the case of males, from their semen.

As the rapist ejaculates into his victim , as many as 400 million of his sperm enter her vagina (or elsewhere) and with his sperm--the DNA genetic code that can identify him. The head of each sperm is stocked with enough DNA in it so that in terms of genetic information, it would be possible to fill dozens of Encyclopedia Britannicas.
There are over 200 billion cells (to twice that number for the obese) in each human being,  and yet DNA is so small, that if it were possible to collect all of the DNA of every human being in the world today, (5 billion of us) all of our DNA could be placed in an eye dropper. 
Coded in the DNA are the complete instructions on how every cell in the body should be built. Of course, DNA is also found in the mother's egg and therefore her heritage is passed on, along with the father's heritage, to the offspring. If the DNA segment that produced brown hair in one parent matches up with the DNA  segment  that  produced  red  hair  in  the  other,  the offspring will have brown hair. If the father has long eyelashes and the mother, short eyelashes, the offspring will have long eyelashes. DNA fixes the amount of earlobe sagging, and decides the width of the ear and the shape of the folds.

Everyone of us has about 200,000 useful control genes in our DNA. It is easy to calculate from skin rejection rates between blacks and whites, how many of them control skin colour differences. There are only four. That means out of 200,000 genes, 199,996 will be left to determine the shape of our heel bones, the width of the main arteries to our livers, the arrangement of nerve cells in our brains ad infinitum.  One could go on and on about just how much the DNA in our cells determines the structure of every part of our bodies but it is suffice to say that all of us are different (with the exception of identical twins) because of the DNA makeup in the cells of our bodies.  If a rapist leaves his semen inside his rape victim,  (or for that matter, even one of his hairs or his flesh or blood under his victim's fingernails) he is in effect, leaving behind for the forensic scientists to discover,  his indistinguishable DNA fingerprints--the blueprint of his genetic makeup.

It was Alec Jefferies,  a geneticist at the University of Leichester in England who in 1983, discovered this breakthrough in genetic 'fingerprinting' as a criminal investigative tool. Using bacterial enzymes as chemical 'scissors', he cut the DNA taken from  several  people  into  segments  and  arranged  them  into patterns that looked somewhat  like  enlarged  bar codes  found  on supermarket products. Since each DNA 'bar code' was uniquely  different,  he had no trouble in ascertaining which 'bar code' belong to which person after he compared each 'bar code' with the others. At that time, it took two weeks to process a sample.

In 1983, a 15-year-old girl was raped and murdered near the English village of Enderby. Her murderer was not found. Then in  July  of  1986,  another  15-year-old girl  was  raped  and strangled in the same area. Soon after that, a 17-year-old youth was arrested in connection with the second murder. It was about this  time  that  Alec  Jefferies  had  come  up  with  his  DNA fingerprinting discovery.  His technique of analyzing the nuclear DNA (as apposed to analyzing the  mitochondrial  DNA)  clearly  showed  beyond  any  doubt  that although the same man killed both girls, the 17-year-old youth was not  the man they were looking for.
The police decided to ask the 5500 men in the area to submit to blood tests for the purpose of determining which of them had the exact DNA 'fingerprint' of the man who murdered the two girls. All of them gave samples of their blood--all accept a 27-year-old baker called Colin Pitchfork. He asked a friend of his to donate his own blood and to say that he  was Colin Pitchfork. The friend later blabbed what he had done in a pub and shortly thereafter, the baker was arrested. He gave a sample of his blood and the comparison was made. His 'bar code' matched that of the murderer's blood on the two victims and he was convicted and sent to prison for life.

This raises an interesting legal issue. Can a suspect be forced to submit to having a sample of blood taken from him for the  purpose  of  determining  if  he  is  the  guilty  party?   The Supreme Court of Canada came down with a decision in December 1988, that fingerprinting suspects who have not been convicted of a crime is not an unwarranted invasion of privacy. The court said that  "a person who is arrested on reasonable and probable grounds that he has committed a serious crime must expect a significant loss of personal privacy."  Justice  LaForest  who wrote  the  decision  of  the  Court,  said  that  fingerprinting suspects charged with an offence does not violate the principles of fundamental justice (if) police have reasonable and probable grounds to believe an offence was committed.
But keeping in mind that fingerprinting suspects is not the same as inserting a needle into their arms for the purpose of drawing blood, it does not follow that this decision is carte blanche authority to hold a murder suspect down and stick a needle into him.  However, this possibility may come about in the future if one of Justice Jeffries statements is taken to the nth degree.  He  said  in  the  'fingerprinting  appeal'   "It  must  be  remembered  that  the  interest  of  the  public  in  law enforcement necessitates  the  subjection  of  the  individual  to  other distasteful procedures."  The police can ask a doctor to take a blood sample from an unconscious driver to determine BAC reading of a patient if the police obtain a search warrant to do so. It may be a big leap from taking blood from unconscious persons to taking it from conscious uncooperative suspects but considering the importance of DNA 'fingerprinting' as an investigative tool, that leap may end up at the end of this century as a mere hop, skip and a jump.

DNA 'fingerprinting' is being used quite extensively by the Americans. For example, in 1986, a Florida court convicted a man on two counts of murder and necrophilia and in the same year, a  U.S.  military  court  in   South   Korea  sentenced  a serviceman to 45 years for rape and attempted  murder.  Both  men  were  convicted  as  a  result  of  DNA  'fingerprinting' techniques. In Wetchester County, N.Y. as many as 200 DNA 'fingerprinting'  specimens  were  presented  to  the  district attorney for evidence but most never went to trial because when the defendants saw the evidence, they pleaded guilty.

There have been some vast strides made in this field and scientists have devised an even more sensitive technique and have  used  it  to  classify  samples  containing  less  than  one nanogram (1 billionth of a gram) of DNA. In fact, they can work with specimens  as  little  as  a  single  DNA  molecule.  Their method relies on a molecular copying process called 'polymerase chain reaction gene amplification', which has been steadily changing the face of molecular biology ever since it was invented in the mid-eighties.  While traditional methods of copying genes or proteins for which they obtain the code, takes several weeks, the newer method thus described can produce millions of copies in less than a day.

It is conceivable that before this century is finished, a  single strand of hair taken from the clothing of a victim, or a minute sample of the rapist's sperm may yield such information  as race, colour of skin, hair and eyes, and whether or not the criminal being sought is large boned or small boned. Such information might even go so far as to state whether he or she has long eyelashes. By putting that information into a computer, within seconds, the actual suspect from the files of known and past criminals may appear on the computer screen. No doubt,  DNA 'fingerprinting'  babies  at  birth  will  be  acceptable  (just  as footprinting them now is) and if this is so, that information will be placed in a master computer and when the identity of a missing person, an unidentified body or a crime suspect is needed, the authorities can go directly to their DNA 'fingerprint' computer files and within seconds, have the name (and probably the picture also) of the person they want to identify.  That's not so far-fetched as one  might think.   With  the  new  computerized techniques that are developed where missing children can be 'aged' on a computer for future identification purposes, it is conceivable that in the future, the information obtained from one nanogram of DNA  can be placed in such a computer so that investigators will  be able to create a likeness of a suspect.

Determining both paternal and maternal parentage is becoming relatively  easy  now  that  DNA  'fingerprinting'  has  been discovered.  In one case, a Ghanaian boy born in England emigrated to Ghana to join his father. When the boy tried to rejoin his mother back in England, the authorities suspected that a substitution had occurred and refused to admit him. DNA 'fingerprinting' determined that the boy was indeed related to his  alleged  mother,  and  the  authorities  permitted  his immigration.
This method of identification is presently helping to identify missing children and victims of disasters and is useful in the research of genetically inherited diseases.
 Sherlock Holmes was great in his day with his magnifying glass in hand, but with the advent of spectroscopy, (instrument used to analyze the molecular structure of evidence left behind in a crime scene) forensic scientists were able to zero in on criminals, but with the discovery of DNA 'fingerprinting', it's beginning to make spectroscopy look like Sherlock Holmes with a magnifying glass in his hand.
On October 12,1989, a 69 year old Nova Scotia woman was brutally raped. The police knew the identity of the man who committed this heinous act. He was even convicted of the crime and given a 6 year prison sentence. Fortunately, a semen sample had been recovered, and a state of the art DNA test had been performed. It proved conclusively that Josh Borden was the rapist. But an appeal court threw the case out because of the way the police had obtained the DNA sample from Borden, despite the fact that the chances of it being wrong are about 1 in 10 million. The prosecutors were not allowed to use this overwhelmingly conclusive evidence because of a technicality which protects the offender.

The elderly lady who was in her bed in a senior citizens' home was sexually assaulted and her life was threatened. She was unable to identify the man because he had held a pillow over her face. A couple of months later another woman was assaulted. Borden was identified and arrested for this second crime.

The police asked him for a blood sample. Borden gave a DNA sample for that offence, and only that offence. The police, who also suspected him of raping the first elderly lady, compared the sample to the semen sample taken from that case. The samples matched. Borden was convicted of the sexual assault of the first elderly woman. However, Borden appealed and the court threw the case out of court because Borden had not been asked to provide a sample for the first crime. The sample was only for the second assault. The 4 year sentence for the second assault is almost up, and soon Josh Borden will be free to walk our streets.


DNA testing, which stands for deoxyribonucleic acid, is essentially the ability to determine a person's biographical fingerprint. Analysts test the highly distinctive strands of the DNA in a sample to determine its origin. Like fingerprints, no 2 people can have the same DNA, save perhaps identical twins. It is estimated that the chance of this kind of evidence being wrong is 1 in 10 million. There are several means of obtaining DNA samples. They are:

 Blood: this is the most common sample that is tested; it can be tested whether it comes in the form of liquid or a stain (however, the material the stain is on can be a factor, i.e. jeans are not good but cotton is); only a small sample is needed; 

Hair: the sample needs to be taken from the root, and about 10 samples are usually required;

Semen:  most commonly found in cases of sexual assault taken from bed sheets or underwear in which only a small sample is required;

Saliva:  often found in sexual assault cases where biting the victim is involved. It can also be found on cigarettes and wine glasses etc.

Bone (marrow); used to determine identity of dead persons

Urine: used to identify a person

Teeth (pulp); used to identify a dead person

Samples up to 5 years of age have been tested. DNA evidence can provide more definite and objective proof of guilt or innocence than can often be provided by eyewitness identification or other such subjective means.

DNA and the law

As is too often the case in Canadian criminal justice history, legislators are too busy catching up to tested and accepted law enforcement techniques to keep up with them. In this case, the technique is DNA testing. Canadian police have been at the forefront of the development of DNA testing in criminal trials. The RCMP opened a national casework service in DNA Typing at the Central Forensic Laboratory in Ottawa in 1989. Yet police and the courts had little to no guidance from the legislature concerning DNA until 1995.

On June 22, 1995 then Justice Minister Allan Rock and then Solicitor General Herb Gray announced amendments to the Criminal Code and the Young Offenders Act that would facilitate the police's role in obtaining DNA evidence. Bill C-104 was proclaimed as law which now permits a judge to issue a warrant allowing police to obtain bodily samples from suspects for forensic DNA analysis. The legislature clarifies the circumstances where the court can be permitted to issue a warrant, the procedure under which suspects can be compelled to provide samples, and how those samples will be taken.

Issuing of a Warrant

DNA is an incredibly powerful revolutionary weapon in the war on crime. Search warrants for DNA samples may prevent future injustices like that of the Borden case. Such search warrants are not much different in theory than obtaining breath or blood samples from a person whom the police have reasonable suspicion to believe may be driving while impaired

In order for a judge to issue a warrant, a police officer must show that there are reasonable grounds to believe that the suspect committed any one of a list of designated offences such as:

 First or second degree murder; manslaughter; assault, aggravated sexual assault, assault causing bodily harm or sexual assault with a weapon, - threats to a third party or causing bodily harm; sexual interference, invitation to sexual touching, or sexual exploitation.

Execution of the warrant

There are three "investigative procedures" authorized under the legislation for the collection of bodily substances such as the plucking of individual hairs from the person; the taking of a buccal swab; and the taking of a small quantity of blood by pricking the skin surface with a sterile lancet.

Destruction of DNA Samples

The legislation contains strict rules governing the destruction of samples taken from a person for forensic testing. In order to protect the privacy of the person, samples of substances seized under the authority of the warrant that remain and the result of the analysis must be destroyed if: the involvement of the suspect in the commission of the offence has been disapproved; the information is withdrawn the prosecution is stayed and not recommenced; or the accused is finally acquitted.

It is important to note that this new legislation can be used in the investigation of offences committed prior to the coming into force of the Act.


DNA has various uses. For example, it was recently used in Ottawa to identify 2 identical twins who had been adopted and accidentally separated at birth. It can identify parents of children in paternal matters. But its use in the criminal justice system may be the most powerful, and also the most controversial. Some of the applications of DNA in law enforcement assist in solving crimes. 

In violent crimes, hair, blood and semen samples are more common than fingerprint evidence. This is especially true for sexual assault cases. Such evidence would make investigations go much quicker. It would not only help implicate the guilty, but it would eliminate the innocent, thus sparing them the pain and embarrassment of being a suspect (it is estimated that more than 35% of the cases received by the FBI result in the exoneration of the accused).

It would allow the police to set up a data base which could include all DNA of convicted sex/violent offenders (see the section on databanks for more information).

DNA evidence could be used to help identify a murder weapon. For example, a knife with blood stains could be tested against the victim's DNA. DNA evidence could be used in homicides, sexual assaults, assaults, hit and runs, etc.

DNA could be used to distinguish "copy cat" crimes from serial crimes.
DNA could connect crimes committed by the same offender, i.e. serial murders.
DNA could determine if more than one offender was involved in a particular crime.
DNA evidence could identify deceased/missing persons.

A study done by the British Columbia RCMP is an excellent example of how effective DNA evidence could be. They have 45 unsolved murders and over 20 unsolved sexual assaults (with DNA evidence), plus several other serious violent offenses in which DNA evidence was available. If, based upon reasonable grounds, police suspect a particular individual committed the crimes above, they will now be able to ask a judge for a warrant to gather DNA from the suspect. If the DNA matches, the cases will be prosecuted without the offender ever having to speak a word.


The legal question of taking a blood sample from an accused person who does not consent is a critical issue. Is it a form of self-incrimination, or does it constitute an unreasonable search? The answers are not clear. When people are pulled over on suspicion of impaired driving, they are required to give a sample of their breath. Could this not be considered to be a form of self-incrimination? If the suspect refuses to give a sample, he/she can be charged. A warrant can be issued for that person's blood if that person is suspected of impaired driving (if they cannot give a breath sample).

However, the more serious a crime is, the heavier the sentence and the greater the stigma. Therefore, the courts may be more stringent on the issues of constitutional rights. For example, it is less serious to be convicted of drunk driving than of murder, so the courts may be more protective of an accused person's rights if the charge is murder. This is ironic considering that the majority of the public might think it is more important to put murderers in prison than it is to put drunk drivers in prison.

Another issue in DNA search warrants is the determination of a standard or threshold of proof to justify the taking of a sample from an accused. The standard for an officer to get a breath sample from a person he/she believes is driving while impaired is reasonable and probable grounds. For example, an officer may see some erratic driving, smell alcohol on the suspect's breath, etc. But, DNA testing is more complicated, and may warrant a higher standard. Defense lawyers are concerned that the police will test everyone until they get a match. While this is far fetched, the question of how much proof is enough must be addressed.

When people are arrested, they are required to undergo fingerprinting. This evidence can be used against them, for example to compare evidence found at the crime scene. The Supreme Court of Canada, in 1988, said that the fingerprinting of a suspect not yet convicted of a crime is legal, and is not an unwarranted invasion of privacy. The court said,

"a person who is arrested on reasonable and probable ground that he has committed a serious crime must expect a significant loss of personal privacy."

In R. v. Alderton, the accused was convicted of sexual assault. He appealed that conviction. The assailant was reported to have worn a nylon stocking over his head during the attack. The officer in charge of the investigation, Detective Ashton, observed some hairs on the nylon stocking that had been left behind by the offender. He wished to compare those hairs with the hairs of the accused. He told the accused that the hairs could be given freely or they could be taken. The accused agreed to give them. Ashton produced a brand new comb, and ran it through the hair of the accused, and the accused also plucked some hairs. Alderton appealed his conviction on the premise that the hair evidence should not have been admitted because it violated s.8 of the Charter (search and seizure). The Appeal Court said,

“It is settled law that following a valid arrest a police officer may search the person arrested and may seize anything that he reasonably believes will afford evidence of the commission of the offence.”

In this case, Detective Ashton had reasonable grounds to believe that the analysis of hair samples from the appellant would connect him with the offence. The taking of the hair samples was not accomplished by violence or threats of violence. It did not contravene section 8 of the Charter.

In R. v. Legere, the appellant was convicted of second degree murder for which he received a life sentence with no parole for 18 years. The case involved the savage beating of an elderly couple in which the man was killed. A sample of hair was found at the scene of the crime. The police, after a discussion with the Crown Attorney, decided to obtain a sample of Legere's hair. Four officers went into Legere's cell (he had been arrested a short time before) and requested some hair samples. He refused. The officers then began pulling hair from his head. The accused then did it himself. Six days later, the police returned with a warrant for the purpose of obtaining more hair samples. The accused did not consent, but he offered no resistance. The hair was needed to place the accused at the scene of the crime. At trial, the Crown conceded that the warrant could not authorize the taking of the hair in that way. The court did find that the samples were taken without consent which is often done in the following manner:

Forcible taking of parts of a person, in the absence of legislation authorizing such acts, is an infringement of the right to security of the person and constitutes an unreasonable search.

However, the judge said that the admissibility of the hair samples did not bring the administration of justice into disrepute, and therefore the evidence should be allowed. It seemed that the judge was sending a message to legislators to pass some laws concerning future situations like that one.

DNA has been used in Canadian courts. For example, DNA testing was allowed in the case of R. v. Parent (1988). Parent had been accused of committing 11 sexual assaults. The Crown believed that all of the attacks were committed by the same man. The attacks were all very similar except for one. DNA evidence was introduced, to which neither counsel objected. However, the DNA tests cleared the accused of several of the assaults. He was convicted of the 1 count that differed from the rest.

DNA evidence was also used in R. v. McNally (1989). The accused broke into the home of a 68 year old woman and sexually and physically assaulted her. She identified him in a police lineup. He pleaded not guilty, and provided a sample of his hair, blood and saliva. The DNA results of these samples were then compared to those of semen found on the bedspread and nightgown of the victim. The judge ruled that such evidence was admissible because it was no different than fingerprint, blood or fibre evidence. After a recess, the accused pleaded guilty and received 7 years.

In R. v. Baptiste (1991), on the question of the admissibility of DNA evidence, the court said,

“Should DNA evidence, because it is relatively new, be treated differently? I think not. If in that the experience in Great Britain, United States and Canada is now sufficient to say that the science of DNA testing is reliable and that where it is relevant and would be helpful to the jury, the evidence should be admitted.”

In reality, the police have had to resort to some pretty imaginative means to try to get DNA samples from suspects, from obtaining a tissue that an individual has used to blow his nose and thrown away to retrieving shed hair. They have also tried to use the common law power of search incident to arrest but with varying success. This refers to the right of the police officer to search an individual upon an arrest. The problem is that this power of search is mainly for the purpose of determining if the individual has any weapons.

An example of a case where the police had to resort to undercover techniques to get a DNA sample is the Ryan Love case. Lucie Turmel, a 23 year old taxi driver, was stabbed to death in Banff. The murderer left his blood smeared inside the cab. The police, using DNA testing, tested samples from a number of people who all gave samples voluntarily. No one matched. They then got a tip on 22 year old Ryan Love. He was asked 4 times to give a sample, and he refused each time. Therefore, two police officers went undercover and befriended Love over the course of one month. They posed as petty criminals and committed bogus robberies with Love. During the course of the month, they obtained a hair sample which was suitable to test for DNA and a tissue that Love had used and discarded. Love's DNA matched and he was arrested and charged with murder. His lawyer argued that Love had been the victim of an unreasonable search, and therefore the evidence should be ruled inadmissible. The judge disagreed and allowed the evidence saying that the violation was trivial in comparison to the possibility of allowing a murderer to go free. Love was found guilty of second degree murder and sentenced to life in prison with no parole for 20 years.


ENGLAND: In 1983, in the English county of Leicestershire, a 15 year old girl was raped and murdered. Her killer was never caught, but semen was recovered. In July, 1986, another 15 year old girl was raped and murdered, and another semen sample was obtained. A 17 year old boy, Richard Buckland, was arrested for the second murder, and he confessed. DNA tests showed that the same man killed both girls, but Buckland was not that man (Buckland became the first murder suspect in the world to be exonerated by DNA evidence). The police then asked the 5500 men in the area to give a DNA sample. All of the men gave samples except for a man named Colin Pitchfork, who asked a friend to go in his place. The friend told other friends what he had done, and it worked its way to the police. Pitchfork was subsequently arrested and he confessed to both murders. He is serving a double life sentence.

U.S.A: The Americans use DNA testing extensively. In the late 1980's, 200 DNA fingerprinting specimens were given to the District Attorney in Westchester County, New York. Most of these cases never went to trial because the accused persons pleaded guilty after seeing the DNA test results. As of January 1, 1990, DNA tests had been admitted into evidence in at least 185 cases in over 35 states. It is estimated that these tests have been used in over 2000 cases, in over 45 states.

The FBI began accepting cases in December, 1988, and reported its first case in March, 1989. By July, 1989, they had received over 2600 samples for over 535 cases, and by February, 1990, they had received over 6375 samples for over 1335 cases. They estimate that they can process about 10,000 samples a year.

The first case in the United States to use DNA was Florida v. Andrews in which the accused was convicted of over 20 cases of sexual assault or attempted sexual assault. DNA tests have been used successfully in cases where the death penalty was given. There have even been cases where the accused requested a DNA test only to have it reveal his guilt.


Critics of DNA worry that the police may over-rely on DNA evidence. In arguing their point, they raise the following problems that can arise with DNA evidence.

Contamination problems: heat;  humidity; ultraviolet light surface sample is found on clothing etc. All of these factors can harm samples. Moisture and high temperatures are the most damaging. Post-mortem samples: state of decomposition, time since death, temperature where body was stored. All of these factors can affect testing.

Not all of these tests results indicate a "yes" or "no" answer. Therefore, these tests should not be interpreted to prove guilt.

Sexual assault cases - it must be remembered that not all males are secreters (about 20% are not). Therefore, the absence of semen does not mean that there was no sexual assault. In many homicides, samples are not available and in many rape cases the only issue before the court is consent.

Other complaints about the use of DNA in the criminal justice system are its great cost and time consumption. Even if a case is high priority, it can still take more than 3-4 months to be completed. The cost of equipment and staff and time are very expensive. But are we willing let money stand in the way of such a valuable investigative aid? What is the cost of not having this evidence? We need only to look to B.C. for the answer. DNA evidence has the potential to save lives by putting murderers and rapists in prison, and it can keep innocent people out. Can we really put a price on something so valuable?

In July of 1996 Mr. Justice Archie Campbell released his recommendations resulting from the Royal Commission into the Bernardo Investigation by various police forces in Canada. In his conclusion and recommendations, he found that " Bernardo's 1990 DNA sample went into a 'black hole' for more then two years, during which time he killed two teenaged girls Leslie Mahaffy and Kristen French, as well as raping four others. "In hindsight, it is clear that these rapes and murders could have been prevented if Bernardo's DNA had been tested earlier." Campbell recommended that all DNA samples be tested within a maximum of 30 days. This sent shock waves through the scientific community as well as the RCMP, who operates one of the only labs in Canada. The government became concerned over the need for more technicians, as well as the very severe financial cost of scientific equipment needed for the labs. The financial burden upon the government thought may be a necessary for long-term savings.

When one factors in the time that police spend investigating a suspect and observing his/her actions, DNA may actually save money. If the police have a suspect, like in B.C., where they do not have enough evidence to press charges and must put the suspect under surveillance, DNA could quickly tell them if they have the right person or not.


As mentioned earlier, there has been much discussion about the development of a DNA databank. The DNA of convicted sex offenders and other violent offenders could be stored into computers which would then be accessible to police forces across Canada. It could provide the ability to do split second searches and comparisons. It would be similar in theory to the Automated Fingerprint I.D. System that is currently available to police. Police forces are able to do a 3 minute scan of millions of prints.

Databanks will assist the police in 3 areas:

1. open cases - police could make searches to determine if cases are connected, and they could test a suspect's DNA against that in storage;

2. missing persons/unidentified deceased victims - DNA could make the identification of these people much easier; and

3. convicted offenders - those convicted of violent or sex offences would have their DNA stored on the computer, and this could cut down on the recidivism rates by having new crimes tested against those in the computer.

In Canada, it was recommended by the Campbell Commission in 1996 that the federal government take steps to build a DNA databank to keep information and DNA found at crime scenes to assist in prosecution, as well as linking offences that may have been committed by the same offender. In September of 1997, Solicitor General Andy Scott announced that a federal databank designed to hold DNA concerning offenders would be in place within the year 1999. This databank, located at the RCMP headquarters in Ottawa, would enlaced DNA samples of offenders convicted of serious crimes, as well as DNA profiles of evidence from the scenes of unsolved crimes.

Over 20 U.S. states have already adopted laws to require testing for some group of violent offenders, and several other states are proposing legislation. DNA results are relatively easy to store in a computer. In fact, the FBI has developed computer software for this purpose. It is hoped that databanks will have an impact on recidivism rates. Released murderers are 5 times more likely to be arrested for murder than are other offenders, and released rapist are 10 times more likely to be arrested for sexual offenses than are other criminals. It is estimated that 60% of offenders who commit 3 violent offences will re-offend, and 80% of offenders who commit 4 violent offences will re-offend. Every time a convicted pedophile re-offends, it costs over $200,000 to prosecute, imprison and treat him/her. If offenders know that their DNA is in a police computer, they may think twice about re-offending.

There are several civil liberty issues surrounding the use of databanks. For example, there are concerns about what information will be stored, which offences require an offender to be in the computer, who will have access to the information, and for what purpose. All of these issues need to be addressed.


Because the results of DNA testing can be so powerfully convincing, and they often are the main reason for convictions, it is important to ensure that such tests are done correctly. DNA testing in general seems to have been accepted by courts as reliable evidence, but there have been specific cases where the tests were not done correctly and the results were not admitted as evidence. Standards need to be set for procedures used, lab performances, accurate record keeping and the storage of the samples for future testing (if necessary). Legislators and professionals should determine these standards together.

There are two particularly interesting American cases which highlight the need for DNA testing standards. The first case is People v. Castro. The accused had murdered his neighbour and her 2 year old daughter. There was a blood stain on his watch that matched the victim's blood. The court allowed the evidence that the blood was not his, but not the evidence that it was the blood of the victim. The court said,

"However the DNA identification evidence of inclusion was deemed inadmissible, since testing laboratory failed in several major respects to use generally accepted scientific techniques and experiments for obtaining reliable results." The accused pleaded guilty in the end."

The second case is State of Minnesota v. Schwartz. The accused was charged with the first degree murder of a stabbing victim. The court rejected the DNA results because they questioned the reliability of the results. It said in part;

“While we agree that DNA typing is generally acceptable, we nevertheless believe the reliability of the tests results is crucial...Cellmark (the man who performed the tests) did not meet all the minimum guidelines...the FBI likely would not consider the tests ready for use in court.”

These 2 cases illustrate the need for universal standards for DNA evidence.


DNA has the potential to save lives. The time to act is now. Laws must be drafted as soon as possible so that no more innocent people are raped or murdered simply because the police are not permitted to do their jobs. The rights of the offenders have outweighed the rights of society for far too long. There is no justification to not allow a technique which can do so much good. DNA is a reality, and it is a part of the criminal justice system. It must be allowed to reach its full potential - to exonerate the innocent and implicate the guilty. The U.S. has already dealt with the issue, and the UK is in the process of drafting legislation.

This kind of evidence will make rapists, murderers and those who defend them very nervous as they are the only ones who oppose such legislation. And it will make law abiding citizens breathe a little easier knowing that sexual predators and murderers of this world are off the streets and behind bars where they belong after their DNA betrayed them.  Critics argue that if the police have the power to demand a DNA sample, Canada will become a police state where citizens live in fear. Many citizens already live in fear, but not of the police. DNA legislation will not affect the majority of Canadians who do not rape and/or murder their victims. And only those who do these crimes have reason to fear. And only they will object. Do we care about their objections? I think not.


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