In one of the early Columbo episodes, when they were still figuring themselves out, there are a couple of scenes where he drops the act. It's one of my favorite bits of the show ever. He's shown beign alone with a victim -something they'd rarely do later on-, who expresses fear that the murderer is gonna get away, so he drops the bumbling fool thing, looks a the victim in the eye and effectively says "nah, I know it was him and I'm gonna nail him". It's a great bit of acting by Peter Falk, but more importantly?
It shows Columbo is out to wreck those guys. Like, maliciously seeking to end them. Actively thinking about how much he's fooling them all the time and strategizing about it. He absolutely knows what he's doing and he'll do it to them on purpose.
If there is a lesson on the ACAB front in Columbo is to not talk to the police without a lawyer when you're facing any legal risk no matter how friendly they may sound.
Peter Falk was great and Columbo was a lot of fun, though.