Columbo's ACTUAL comic book appearances -- cameos, really -- happen in The Brave and the Bold vol.1 No.109 (Oct 1973, “Gotham Bay, Be My Grave”) and then again in Adventure Comics vol.1 No.439 (May 1975 “The Voice That Doomed the Spectre”), below:

In the second pic, is Columbo talking to Inspector Cluseau?

okay that dude's gloved hand breaking the panel boundary is fuckin shit hot, early-'70s comics man