From: "Peter Mackay" peter.mackay@bigpond.com
If a person had admitted guilt, then there is no problem. We may describe them as a criminal. But if they maintained their innocence and were found guilty instead of pleading guilty, then we should use conventional phrasing to indicate this, by describing someone as a convicted rapist, rather than a rapist.
People also falsely confess to crimes; there have been many famous cases of this which have actually been later overturned (and one must assume even more cases which have not been overturned). If we start trying to second guess legal systems, then all we'll be left with is original research to determine if someone is a criminal.
Jay.