Legal Question in Criminal Law in Michigan

Re: jury contamination

I'm only responding to the opening phrase of your message ("can a prosecuter bring up a defendants past record to discredit his testimony on a case") because the rest add irrelevant issues.

Under the Michigan Rules of Evidence, any witness' past criminal record cuold be admissible to impeach (challenge) their credibility ... but it has to be:

(a) a crime involving an element of dishonesty or false statement [e.g., embezzlement, forgery, knowingly passing a bad check],

or

(b) a felony crime where one element is "theft" AND the court determines that the evidence of theft has a significant effect on proving lack of credibility (further, if the witness is the criminal defendant, the judge has to rule that the probative value (usefulness) of the evidence is not outweighed by its prejudicial effect on the defendant. [So, if the person was convicted of having stole a 5 cents piece of candy, that conviction is likely inadmissible because it really doesn't taint the person with credibility problems as much as if the conviction was for $100,000 in a course of repeated acts over a year from a church.]

Prior convitions might also be used by a prosecutor to prove, for example, that the defendant committed THIS crime (e.g., home invasion) because it was done in the same way as other past home invasions he'd been convicted of in the past. (A distinctive pattern, plan or system of doing a crime. Hollywood calls this a "M.O." or modus operandi.) But the prosecutor has to put the defendant on advanced notice about this. Sometimes a hearing is required for the judge to learn about the details of the other crime(s).

Bottom line: Not all past convictions are used. Some may, some might not, depending on the crime, the facts of the prior crime, and most importantly why the past conviction is trying to be used.