Well, seeing as this thread is already running, and being totally honest here, i personally would imagine the truth is somewhere between what he was rumoured to have done, and what he got prosecuted for doing, as fuck me you would have to be properly unlucky to get caught the one and only time you ever broke the letter of the law.
Bottom line is though, Martin is well and truely trustworthy these days in the experience of myself and everyone else I know, and with a criminal record that would result in no doubt the book being thrown at him, and with so much to lose, I really cant see him ever wanting to take risks with the law again, so im positive personally that he will stay totally legit as he learnt the hard way what can happen if you dont.