In Canada, polygraph (lie detector) test results are strictly inadmissible as evidence in criminal trials. Following the Supreme Court of Canada’s decision in R. v. Béland, judges and juries cannot use these tests to determine guilt or innocence. However, Canadian police still use them extensively during investigations as an interrogation tool to extract confessions.
Many Canadians believe that passing a lie detector test can instantly clear their name, a myth heavily fueled by American television and movies. In reality, the Canadian criminal justice system views polygraph machines with immense skepticism. The Supreme Court of Canada has definitively ruled that the results of a polygraph test cannot be introduced as evidence in any criminal trial, whether to prove you are telling the truth or to suggest you are lying.
Despite this clear legal ban in the courtroom, the Royal Canadian Mounted Police (RCMP) and local municipal police forces still employ polygraph examiners. They use these machines as an investigative psychological tool. If a police officer asks you to take a polygraph, understanding your rights under the Canadian Charter of Rights and Freedoms and the actual legal weight of the test is crucial to protecting yourself against wrongful self-incrimination.
Step-by-Step Process: How Police Use Polygraphs in Canada
Because polygraph results cannot be used in a trial, police use them to steer their investigation. The process is entirely voluntary, and understanding how law enforcement leverages the test can help you make an informed decision alongside your lawyer.
Step 1: The Voluntary Police Request
During an investigation for a serious indictable offence, a detective may ask you to submit to a polygraph test to “clear your name.” You have the absolute right to refuse. In Canada, no one can be forced to take a lie detector test. Refusing the test cannot be used against you in court as evidence of guilt.
Step 2: The Pre-Test Interview
If you agree to the test, you will be placed in a room with a specialized police examiner. Before the machine is even turned on, the officer will conduct a lengthy pre-test interview. This is actually a sophisticated interrogation technique designed to build rapport, observe your baseline behaviour, and lock you into a specific version of events.
Step 3: The Polygraph Examination
The examiner will attach sensors to measure your heart rate, blood pressure, respiration, and sweat gland activity. They will ask a series of simple control questions followed by direct questions about the crime. The machine does not detect lies; it only detects physiological stress, which can easily be triggered by the sheer anxiety of being interrogated.
Step 4: The Post-Test Interrogation
This is the most dangerous phase. Regardless of what the machine actually recorded, the officer may tell you that you “failed” the test. They will use this fabricated or real failure to pressure you into confessing. While the polygraph results are inadmissible in court, any voluntary confession you make during this post-test interview is fully admissible against you.
Why Polygraphs Are Excluded in Canadian Courts
| Legal Principle | What It Means | Impact on Trial |
|---|---|---|
| The Oath-Helping Rule | Witnesses cannot use artificial means to bolster their own credibility. | You cannot bring a “passed” test to prove you are an honest person. |
| Hearsay Evidence | The machine’s “opinion” cannot be cross-examined by the Crown or Defence. | Keeps unreliable, pseudo-scientific opinions out of the courtroom. |
| Jury Usurpation | Determining who is telling the truth is the strict job of the judge or jury. | Prevents a machine from replacing the human element of justice. |
How Much Does a Polygraph Cost in Canada?
While a police-administered polygraph is free, sometimes a defence lawyer will suggest hiring a private examiner to convince the Crown Prosecutor to drop the charges before trial.
- Private Polygraph Examiner: Generally costs between $500 and $1,500 CAD depending on the complexity of the questioning.
- Lawyer Consultation Fees: A criminal defence lawyer will typically charge $200 to $500 CAD per hour to advise you on whether submitting to a test is strategically wise.
- Important Note: Even if you pay for a private test and pass with flying colours, the Crown is under no legal obligation to drop the charges, though it may influence their internal assessment of the case’s strength.
How Long Does the Process Take?
If you agree to a police polygraph, the entire appointment usually takes between 3 to 5 hours. The actual time attached to the machine is quite short (often under 30 minutes), but the pre-test interview and the aggressive post-test interrogation consume the bulk of the time. The legal consequences of a confession obtained during this period can last a lifetime, emphasizing why securing legal counsel beforehand is critical.
Frequently Asked Questions (FAQ)
Can an employer force me to take a polygraph in Canada?
Generally, no. Most Canadian provinces have strict employment laws (such as Ontario’s Employment Standards Act) that explicitly prohibit employers from requiring employees to take a lie detector test as a condition of employment or during workplace investigations.
If I fail the police polygraph, will I be arrested?
Failing a polygraph test alone is not sufficient grounds for an arrest or a conviction, as the results are legally meaningless in court. However, if you fail and then subsequently confess to the crime during the interrogation, that confession will lead to your arrest.
Are polygraphs used in family or civil courts?
No. Just as in criminal courts, family court judges and civil adjudicators across Canada generally reject polygraph evidence. Matters of child custody or financial disputes rely on documentary evidence and witness testimony, not physiological stress machines.
Should I take a polygraph to prove my innocence?
You should never agree to a police polygraph test without first consulting a criminal defence lawyer. Because the machine measures stress, an innocent but highly nervous person can easily fail, leading to aggressive police interrogation and potentially false confessions.
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