The latest in my ‘Learn Something New Every Day’ series – taken from The Great Courses’ “Trails of Evidence: How Forensic Science Works” (Lecture 30: When forensics are on trial)
In order to be admissible in court, evidence must meet criteria of relevance (pertaining to the matter at hand) and probative (has to prove something in the case).
Relevance is why past crimes are inadmissible in a trial. But, if the prosecution wants the jury to hear that information, they are allowed to ‘test the truthfulness’ of a defendant by asking them under oath about prior convictions. That is the reason that many defendants don’t testify. If lawyers can’t ask a defendant because they opt out of testifying and it’s important to their case, attorneys must try to expose the thruth through other legal means.