When you enter a Plea of Guilty and that plea is accepted by a Judge, you are for all intents and purposes convicted. A judge at that point only needs to address sentencing. The problem is that he skipped the country prior to sentencing. From that point on, he is simply evading or escaping his sentence. His supposed reason for running was that he believed that the terms of the plea were not going to be followed. If that was the case, running is the last thing you should do! Further, the victim has won a settlement against him. A man of means, under these circumstances has no excuse for not settling his debts. In fact had he simply paid the monies owed, this may have never happened. If nothing else he is definitely guilty of REALLY BAD JUDGEMENT! To answer your question he was convicted the day (1977) he entered into a plea agreement with the DA.
I am also annoyed that so many actors and actresses are starting petitions and groups in support of him. Just because he may have produced award-winning films certainly doesn't give him the right to get away with the crime. Whoopi Goldberg even said on "The View" that she didn't think it was actual "rape" because it was consensual. I think that if someone is so young, they may regret their decision later, even if they did get to "choose" (though allegations are that the 13-year-old model was drugged).
Now, now, now, he's just a misunderstood artist who is working on a different plane than the rest of us. It takes alittle extra to keep an artist at the top of his game. You can't possibly expect him to create something beautifull without some artistic license.
Yeah, it's really disgusting how many other Hollywood types are defending him. I suspect the whole case probably hits a little close to home for many of them - who knows how many actresses (and even actors) are as famous as they are now because they slept with the right producer back in the day? Granted, most of them probably weren't terrified, protesting 13 year olds pumped full of Quaaludes when it happened... (Somebody posted the girl's testimony online - reading through it is really upsetting, especially as the parent of a young daughter.)
A lot of feminists I know are talking about a boycott of the actors, directors, etc. who have signed the petition - one of the few times I think you'll ever see feminists and social conservatives agreeing!