Well the charge was accessory and I would imagine that, considering she was quite instrumental in carrying out the murder plan so they should have equal culpability. It was definitely premeditated and that's usually murder one.
I love that little drama act she was giving to Columbo about signing the divorce papers while he was puffing on his cigar in her living room. He was probably thinking she should charge admission to such an performance. He didn't buy a syllable of it.
Even though her several seasons on FALCON CREST somehow didn't do it, that character gave me kind of a crush on the actress Jamie Rose. So I have kind of mixed feelings about her getting in trouble along with Leon.
I never understood why Leon would get her in on the murder. Once she's in on the plan, Leon has to give her half. Surely he could have worked out something else and still hooked up with her, if that truly was his goal.
I agree that it's a fantastic episode. A lot of Columbo fans dismiss all of these later episodes and I think that's a mistake. I agree that the 87th precinct episodes along with Murder in Malibu and a few others actually diminish the entire character, but most of the later episodes work at least on some level.