Obviously it's already happened now but that came from Ausiello as well. He posted it months ago, actually - back around the hiatus period, he said that Charlie would return for an episode towards the end of the season, and would die in the same episode he came back in. Actually I think he called him by the actor's name rather than the character's, but I don't recall who plays Charlie at the moment.
IIRC, Dean Winters will be a series regular on a new show this fall, so these two elements (or rather three, if we count Ausiello's spoiler) were probably connected.
Edited by grim squeaker, Mar 30, 2009 @ 12:15 PM.