In Plain Sight - Season 2 Episode 6 -

The Albuquerque P.D. finds a body buried and with it Stan's old id. When Stan arrives he says he thinks the body was the first witness he handled: a comedian named Willie Rip. Willie was performing in a club owned by criminals at that time and saw them kill someone. The criminals were about to kill him when his girlfriend Gwen saved him, and following this they both entered the witness relocation program. Stan misses out details of Gwen when re-telling the story for Dershowitz. And when Dershowitz asks for the man's file, Stan withholds part of it.