“Brian Leslie is essentially saying the same thing your mother did— “don’t jump to conclusions.” But the forensic deception expert is saying it to cops as a potential way to reduce wrongful convictions and instances of profiling—a number he thinks can be improved by at least 30 percent.

Leslie, who works with Criminal Case Consultants analyzing witness testimony in wrongful conviction cases, says the difference lies in the predisposition of the police officer, which subsequently affects how s/he vets witnesses and the information they provide.

A “predisposed officer” who has formed an opinion based on emotion is more likely to disallow or overlook information that is averse to the officer’s initial, kneejerk theory of the perpetrator. According to Leslie, this predisposition is the main reason officers both subconsciously and consciously profile specific groups of people.

To rectify this, Leslie suggests using a different type of investigational method.

Traditional police criminal investigations use a deductive method, in which an initial theory is formed based on information provided by witnesses and/or confidential informants. However, Leslie says by using an inductive method of investigation, it detaches the officer from the emotional elements of a case, allowing a more analytical vetting process.

Simply put, this means the officer analyzes witness credibility first, and then the information provided. This inductive process forces the officer to accept all information by all sources, then categorize it by relevance and credibility. It’s this small investigational difference Leslie points to as being the culprit behind wrongful convictions that can, literally, destroy lives.

The variance between deductive and inductive investigations is part of what Leslie calls the “Mr. X Theory,” which he expands upon in his new book, “Visual Liar.”

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