Heather Mac & Mr. Placid are correct.

It depends. Usually previous criminal acts are not admissible, but there are exceptions. The more common ones:

1. Criminal convictions are admissible to prove motive, intent, plan, preparation, opportunity, identity, or common scheme. (See, e.g. Fed. Rules of Evidence 404(b))

2. Criminal convictions are admissible to impeach a witness (attack the credibility of a witnesses’ testimony) on cross-examination. Witness includes a defendant who takes the stand in his own defense. (Fed Rules of Evidence 608(b))

There are a few others. But, the bottom line is that prior criminal acts are NOT automatically inadmissible.

Can it be presented to the jury as evidence? Probably not.

Is it known by the police & prosecutor prior to charges being brought against you? You bet your ****.

Your past will always come back to haunt you if it is permanently recorded.

No, it cannot be used as evidence against you. The fact that you committed grand theft in your past is irrelevant to whether you committed murder in this instance. They only purpose it would serve would be to prejudice the jury. However, if you chose to testify, the prosecutor can ask if you have been convicted of a felony. But, they cannot go into what the felony was unless you lied and said “no”. Of course, if your previous conviction was for a murder that occurred in the same manner as the murder for which you were being tried, the prosecutor could make a motion to get that previous conviction in as evidence of Modus Operandi.

sometimes if they indicate a persons moral standards and they are relevant to the current case.

Normally not. Past crimes are usually entered into court to show a pattern of committing the same type crime. As usual, there are always exceptions.

No. The fact that you may have committed grand theft in the past is not evidence that you committed murder. It would be taken into consideration when determining a sentence after conviction.