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Expert witness Blog

Types of Expert Witnesses in Criminal Defence in Alberta

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As science and technology advances, criminal courts across Canada, including Alberta, have come to understand that expert witnesses hold a unique role in court. These individuals must demonstrate specific “scientific, technical or specialized knowledge” to be qualified by the court as an expert in their field in order to examine relevant materials and provide relevant opinions based on their expertise. 

Expert Witness Criteria and Their Role in Criminal Law

The expert’s role is to assist and educate the court by providing an independent and unbiased opinion about matters within their expertise. This unique position allows the expert witness to become a key figure, offering insights that can influence the judge’s findings and, consequently, the outcome of a criminal case.

If certain admissibility criteria are met, the expert witness is often the only type of witness permitted to testify based on their opinion. For more information about these criteria and the admissibility process, you can visit our article here.

Types of Expert Witnesses

There is a wide array of expert witnesses who can bring their knowledge into a criminal case. For example, if the prosecution relies on DNA to prove guilt beyond a reasonable doubt, a DNA expert’s testimony can call it into question. Depending on the facts, expert witnesses may also challenge other evidence in a criminal case, such as firearms, weapons, fingerprints, and toxicology tests, among others.

 The most commonly utilized experts in criminal trials include:

  • Forensic Scientists
  • Psychologists
  • Ballistics experts
  • Financial experts
  • Medicine, Science, IT experts & more

Forensic Scientists

Forensic scientists are often at the forefront of criminal investigations, analyzing physical evidence to uncover the truth. Their expertise includes various disciplines, such as DNA analysis, toxicology, fingerprint analysis, and trace evidence examination.

In a criminal defence context, these experts question the integrity of evidence by reviewing the procedures followed during its collection, preservation, and analysis. Any deviations from standard protocols can lead to contamination or misinterpretation of evidence, casting doubt on the prosecution’s case.

Forensic scientists can also present alternative scenarios based on the evidence, offering explanations that support the defence’s narrative. For example, they might argue that DNA found at a crime scene could have been transferred innocently or that a substance identified as a drug was, in fact, a legal compound. 

Psychologists and Psychiatrists

Psychologists and psychiatric experts play a special role in criminal cases where the mental state of the accused or a witness is in question. Their assessments and opinions can significantly influence the jury’s perception of key aspects of the case.

Psychiatric experts provide insights and education on how specific illnesses may affect thinking, decision-making, reality testing, mood, judgment, and cognition. They apply this knowledge to evaluate competency and insanity, determining whether a person qualifies for a defence of not guilty by reason of insanity or if they are competent to stand trial. In Canadian law, these concepts are referred to as “not criminally responsible on account of mental disorder” (NCRMD) and “fitness to stand trial,” respectively.

Psychologists can also analyze witness credibility by evaluating the reliability of witness testimony, particularly in cases involving memory recall. They can explain how factors like stress, suggestive questioning, or trauma can affect a witness’s recollection of events.

Firearms & Ballistics Experts

In cases involving firearms, ballistics experts provide critical insights into the mechanics and effects of weapons. Their importance in legal proceedings lies in their proficiency in analyzing bullet remnants, bullet trajectories, and the various weapons used in crimes.

Their testimony can clarify crucial details about the crime by reconstructing the events of a shooting, either corroborating or contradicting the prosecution’s version of events. 

Ballistics experts can also determine whether a firearm was functional and capable of firing during the incident. Additionally, they can identify if a particular gun was used in the crime based on unique markings left on bullets and casings.

Firearm experts can even be used to disprove firearms possession based on where fingerprints are located on firearms. 

Facing firearms charges? Please visit our firearms defence section here.

Financial Experts

Financial experts are usually called for fraud and other criminal cases of a financial nature.

These specialists can play a key role in criminal cases involving economic crimes such as fraud, embezzlement, and money laundering. Their expertise in accounting, finance, and economic analysis allows them to analyze complex financial transactions and uncover discrepancies that may indicate criminal activity.

Financial experts review records, transaction histories, and audit trails to identify errors or misinterpretations. By doing so, they can challenge the validity of the financial evidence presented by the prosecution. Additionally, financial experts can offer alternative explanations for financial irregularities. For example, they might demonstrate that certain transactions were legitimate business activities or that apparent discrepancies were due to accounting errors rather than fraudulent intent.

If you’re looking for a fraud or money laundering criminal lawyer in Alberta, contact Davidson Gregory today.

Other Experts

Apart from clarifying scientific and technical matters, expert witnesses can evaluate the credibility of eyewitnesses and the authenticity of their testimony. They may also challenge the prosecution’s case by offering alternate interpretations of theories. In addition, some types of experts may be brought into a case to reconstruct the crime scene. No matter what type of witness is used, their role is to help your criminal lawyer introduce reasonable doubt and undermine the prosecution’s case.

Davidson Gregory has the legal experience to know which cases require the use of experts and which do not.

Expert witnesses come from diverse professional backgrounds, each bringing unique skills and knowledge to the courtroom. Their specialized insights can meticulously analyze evidence, offer alternative interpretations, and provide context for the defendant’s actions. They educate the court and offer unique perspectives that can significantly impact the trial, ensuring all aspects of the evidence are thoroughly examined and fairly considered.

Witness Selection by Alberta Criminal Defence Lawyers

At Davidson Gregory, our criminal defence lawyers understand when expert testimony is needed and when it’s not. We evaluate each client’s situation to provide informed guidance. This tailored approach ensures resources are used efficiently, focusing on strategies that best serve the client’s defence needs. Contact our experienced criminal lawyers today.