I think the Ken Archer scenes in "Death Lends A Hand" are different. That shows the early Columbo not weighed down by "gimmicks" who is doing some genuine investigating. He might know that Archer didn't do it because of the ring issue but he also from an investigating standpoint needs the full information on Archer's relationship with Mrs. Kennicutt. He has to make him sweat just a little bit to get that information and *then* he can tell him he's in the clear.