Judging by other threads here, and looking at the help section, it should be technically possible. Heck over at Litecointalk you can do it yourself, and it looks like the same forum software.
He's said before he doesn't do it anymore.
1) Make sure that the account wasn't hacked.
2) Check for any existing scam accusations against the person.
3) Check their outbound PMs for scammy behavior.
This is a long, painful process, so theymos just doesn't do it anymore.
And even if you delete all your posts, they are still archived somewhere on the web...