Dr. Moon has shown up as a defense attorney several times, most infamously as that for Matt's killer.
Irony As She Is Cast: Matt butchering the French language when trying to talk to a witness when in Real Life, Jamie Bamber speaks excellent French (it's one of two languages, the other being Italian, that he studied for his Modern Language degree).
McLeaned: Matt Devlin was killed in a drive-by shooting when actor Jamie Bamber finished his contract. The writers probably wanted to kill off a major character to provide good drama, so it's a pretty classic example of Reason #1 — the following episode was one of the series best as the team struggled to deal with their grief while doing their best to ensure that his killer was brought to justice.