One of the greatest advancements in forensic research has been DNA testing. The media tends to portray this type of evidence as the answer to all of our criminal justice problems, as if all it takes to solve a crime is to have DNA available. The truth is there is a procedure before DNA testing can take place, and in order to protect our individual rights the police cannot obtain this evidence without a warrant.

Search warrants must be issued to a peace officer for this evidence to be obtained from a suspect; these provisions provide us with assurance that officers may not simply walk up and demand a DNA sample. The importance of search warrants presents the possibility, however, that culprits may be released due to improperly gathered evidence. As in most areas of law, the rules are clear and objective, while the means are usually subjective and in the judge’s discretion.

What Is DNA?

DNA, which stands for deoxyribonucleic acid, can be thought of as a person’s biological fingerprint. Analysts test the highly distinctive strands of DNA in a sample to determine its origin. Like fingerprints, no 2 people can have the same DNA, except for 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:

  • Blood: The most common sample tested. Blood can be tested in liquid form or from a stain, depending on the given material (jeans are not a good material to extract DNA from, cotton is usually better).
  • Hair: The sample needs to be taken from the root, and about ten hairs are usually required.
  • Semen: The most commonly found sample in cases of sexual assault, taken from bed sheets, a victim’s clothing, or general surfaces from the crime scene.
  • Saliva
  • Bone (Marrow)
  • Flesh
  • Urine
  • Teeth (Pulp)

Police must have a warrant to obtain a sample of a person’s DNA, and once the warrant is issued they must gather the evidence by 1) Plucking individual hairs, 2) Swabbing the inside of the mouth, and 3) Pricking the skin. Samples up to 5 years of age have been tested. DNA can provide a more definite and objective form of evidence than can often be provided by eyewitness identification or other such subjective means.

DNA and the Law

When DNA is obtained from a suspect, it is meant only to be used for the specific case under investigation and not to be entered into the national DNA data bank. This regulation is in place to protect our assumed innocence in the eyes of the law. Prior to collecting DNA evidence from a suspect, the officer must explain to the suspect everything that the warrant stipulates and how the evidence will be used. If the sample is obtained in a manner contrary to the Charter of Rights and Freedoms, the sample is void and cannot be used as evidence.

Issuing of a Warrant

For a judge to issue a warrant, a police officer must show that there are reasonable grounds to believe that the suspect committed one of the designated offences:

  • 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.

Section 487.05 of the Criminal Code outlines the provisions for obtaining DNA evidence.

487.05: (1) Information for warrant to take bodily substances for forensic DNA analysis. A provincial court judge… is satisfied by information on oath that there are reasonable grounds to believe

  • That a designated offence has been committed
  • That a bodily substance has been found or obtained
  • That a person was a party to that offence
  • That forensic DNA of a bodily substance from the person will provide evidence about whether the bodily substance referred to was from that person

While the judge considers whether a warrant would be appropriate he must acknowledge if there is a peace officer available to obtain the sample within the provisions of this section, or if another person is able to obtain it, under the supervision of a peace officer. Warrants are also admissible over the phone in cases where an officer believes scheduling a meeting would be impractical. During deliberation, judges consider the suspect’s criminal record, the nature of the offence, the situation surrounding its commission, and how the warrant would impact the individual.

After it has been decided that a warrant is justifiable, the procedure is specified. The amount of DNA necessary is determined. The suspect may have to report to a certain location at a designated date and time. If the individual fails to appear, a warrant for arrest may be filed to allow an officer to obtain a DNA sample. There are three scenarios in which a judge can issue a warrant to obtain DNA from an already convicted criminal:

  • The individual has been declared a dangerous offender;
  • They have been convicted of more than one murder at different times;
  • They have been convicted of more than one sexual offence and are serving at the time of application a sentence of at least two years.

Execution of the Warrant

The warrant is considered valid until it is executed by a peace officer or under the supervision of a peace officer. Before obtaining a DNA sample, the officer is required to check if the suspect is already in the convicted offender’s index, in which case they cannot take another sample. The DNA is not permitted to be used for any other purpose than the specific case in the warrant. Violation of this rule can be either a summary or an indictable offence. There are three investigative procedures authorized under the legislation for the collection of bodily substances. They are:

  • 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 DNA act contains strict rules governing the destruction of samples taken for forensic testing. In order to protect the privacy of the person, samples seized under the authority of a warrant and the result of the analysis must be destroyed after a year’s time 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 has been acquitted.

A judge can counteract this rule if they suspect that the sample given can be used in the investigation of another offence. Bodily substances have to be destroyed immediately if it is proven that the sample was not from the intended individual.

DNA Applications

There are several ways that DNA can be used. It can be used to identify parents and blood relatives. Samples have been used to identify identical twins that had been accidentally separated at birth. Its use in the criminal justice system may be the most powerful, and also the most controversial, of all. Some of the applications of DNA in law enforcement are:

  • In violent crimes, hair, blood and semen samples are more common than fingerprint evidence. This is especially true for sexual assault cases. Such evidence makes investigations go much quicker. It not only helps implicate the guilty, but it eliminates the innocent, thus sparing them the pain and embarrassment of being a suspect.
  • It allows the police to set up a data base which could include DNA of all convicted sex/violent offenders.
  • DNA evidence can be used to help identify a murder weapon. For example, a knife with blood stains may be tested against the victim’s DNA.
  • The sample gathered can potentially distinguish a ‘copy cat’ offender in a serial crime spree by revealing their different DNA, or connect seemingly unrelated crimes committed by the same offender.
  • It can determine if more than one offender was involved in a particular crime.
  • DNA evidence has the potential to identify deceased persons and human remains.

Legal Issues Concerning DNA Evidence

Serious legal questions surrounding the act of taking a blood sample from an accused person who does not consent. Is it a form of self-incrimination? Does it constitute an unreasonable search? The answers are not clear. When pulled over on suspicion of impaired driving, people are required to give a sample of their breath, and this is generally accepted as not constituting self-incrimination. If the suspect refuses to give a sample, he/she can be charged. A warrant may be issued for a blood sample to be taken from the individual if a breath sample cannot be given. Thus, there is analogous precedent.

The more serious the crime, the greater the resulting sentence and stigma. Since the costs of a guilty verdict carry a lot more weight for serious offences, the courts tend to be stricter in protecting the Charter rights of accused being tried of a serious offence. This is why it is much harder to lawfully obtain a DNA sample in a murder case, compared to a breath sample in a drunken driving offence. Setting the standard of proof necessary to take a sample of DNA from a suspect is another prominent issue. The standard required for an officer to demand a breath sample from a person he/she believes is driving while impaired is reasonable and probable grounds. For example, an officer may see erratic driving or smell alcohol on the suspect’s breath and demand the offender take a breathalyser test. DNA testing, however, is more complicated and warrants a higher standard of proof. Ideally, the strict guidelines surrounding the issuing of a warrant to obtain a sample of DNA strike a balance that protects individual rights while also aiding investigation.


On April 12, 1991 a group of teenagers went on a late night camping trip where they consumed beer and wine and shared LSD. William Stillman, 17, and Pamela Bischoff, 14, decided to go off by themselves. Stillman arrived home later that night covered in mud and with a cut above his eye, claiming that he was in a fight. Six days later, Pamela’s body was found in a river near the camping site. Several motorists identified Stillman after seeing him walking on the bridge just over the river. The autopsy revealed the cause of death was several blows to the head, and semen was found inside the victim along with a bite mark on the abdomen.

Stillman was arrested for murder and the police forcefully obtained hair samples and teeth impressions, followed by an hour long interrogation without counsel. During the interrogation the accused blew his nose with a tissue and threw it out, the officer retrieved the tissue and used it for DNA testing. The accused was found guilty of first degree murder and appealed the decision, claiming that his Charter right from unlawful search and seizure was violated. The courts held that since the DNA from the tissue proved conclusive, and that was the piece of evidence that was lawfully obtained, the appeal should be dismissed. It is almost certain that if the accused did not use a tissue, the rest of the evidence would have been inadmissible and the accused would likely have been acquitted.

In a more recent case, R. v. S.A.B., the accused was charged with sexual assault and sexual exploitation. The victim, a 14 year old girl, discovered she was pregnant in 2002 and told her mother that she had been sexually assaulted. After S.A.B. was arrested officers obtained a warrant and took a blood sample to compare to tissue taken from the victim’s aborted fetus. After the DNA test revealed that the accused was not the father, the exploitation charges were dropped and he was tried and convicted of sexual assault. S.A.B. appealed the decision to the Supreme Court of Canada, claiming that the provisions for gathering DNA violated his Charter right to be free from unlawful search and seizure, and his right to life, liberty, and security of the person. The Supreme Court upheld the DNA Identification Act.

Possible Problems with DNA Evidence

Critics of DNA evidence worry that police may rely on it too heavily and that courts may treat it as irrefutable. There are, however, some limitations:

  • Sample damage: Heat, humidity, and ultraviolet light can all damage DNA samples, preventing their use for comparative identification.
  • Post-mortem samples: The state of decomposition, time since death, temperature in which a body was stored all affect the quality of DNA that can be extracted.
  • Sexual assault cases: Not all males are secretors (about 20% are not). Therefore, the absence of semen does not necessarily mean that there was no sexual assault.
  • Cost and time: Even if a case is high priority, it can still take more than 3-4 months to complete genetic tests. Equipment, staff, and time are very expensive.

In July of 1996 Justice Archie Campbell released his conclusions and recommendations for the Royal Commission into the Paul Bernado investigation. He found that “Bernardo’s 1990 DNA sample went into a ‘black hole’ for more than two years, during which time he killed two teenage 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 operated one of the only labs in Canada at the time. The government became concerned over the need for more technicians and the severe costs of the scientific equipment needed. However, if the time that police spend investigating and monitoring suspects is taken into account, DNA testing may actually save money. DNA can give police the threshold evidence needed to press charges without having to put them under surveillance.

DNA Identification Act

This Act outlined the provisions necessary for the creation of a national DNA databank in Canada. The first underlying principle of this database is that using DNA profiles will serve society because re-offenders will be easily detected, arrested, and convicted. Secondly, the data gathered may only be used for law enforcement. Thirdly, safeguards have to be placed on the information to protect the privacy of those individuals in the database. The document also states that DNA profiles can facilitate the early detection of offenders, which is in society’s best interests. These profiles are restricted to law enforcement purposes; any use of DNA outside criminal investigations is strictly prohibited. By September 2010, the databank had linked 16,577 offenders to crime scenes and 2,316 crime scenes to other crime scenes. Without the databank the vast majority of these links would never had been made.

DNA Testing Standards

Since the results of DNA testing can be so powerful, and they often are the major evidence for convictions. It is therefore important to ensure that such tests are done correctly. DNA testing in general has 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 maintained for procedures used, lab performances, accurate record keeping and the storage of samples for future testing. The FBI has a list of standards that include:

The laboratory shall:

(a) Have a managerial staff with the authority and resources needed to discharge their duties and meet the requirements of the standards in this document. (b) Have a technical manager or leader who is accountable for the technical operations. (c) Specify and document the responsibility, authority, and interrelation of all personnel who manage, perform or verify work affecting the validity of the DNA analysis.

Without testing standards, results may be skewed and undermined because of a lack of consistency. By having a set list of rules and regulations governing DNA testing, the courts can have greater confidence in its reliability. These rules also guard against corruption within the lab, ensuring that since extensive records are kept and more than one person handles testing, it is less likely that individuals will act in their own self interest. By ensuring the dependability of DNA evidence, these standards strengthen its role in court.


There is no doubt that DNA evidence is an extremely powerful tool in the criminal justice system. The need for a search warrant to obtain a sample of DNA protects our civil liberties, especially since the act of DNA gathering is more invasive than for most pieces of evidence. Maintaining fair and legal use of DNA also makes DNA evidence stronger, more reliable, and less likely to be challenged in court. DNA testing has advanced considerably since its first use in 1989. By monitoring both those being tested and those testing DNA samples, we can ensure that this tool is being used for the betterment of society. DNA search warrants are vital in regulating the use of DNA evidence.

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