I while ago I looked into the close up of Columbo’s driver’s license (also shown in this forum) and after clarifying the picture, it appears to say, “Frank.” Just a thought, but I think the writers were also having a bit of a joke with that, because in several episodes (especially the earlier ones), Peter Faulk says the line, “Let me be Frank.” So I always assume that (informally) that was his first name.

I also happen to have that trivial pursuit game and I never understood how it could ever be Philip. :)

I’m not very active on this forum, but I probably put on N old Columbo episode about once a week while I clean.

what episode was that where it shows his drivers license? I'm thinking Negative Reaction?

I'm not sure which episode it is, but indeed I remember reading about an episode where it shows his driver's license, I'm sure on columbophile website there's an article talking about columbo's first name and about that scene in that episode.

Also there's an episode, undercover, where he says his real name is Lieutenant! He does that when Geraldine Ferguson asks him, their last conversation before she's mudered.