Since I am home alone I have been doing a lot of Columbo watching. I just watched the best episode I have ever seen and I highly recommend it. Season 5: Forgotten Lady.
In this episode Columbo solves the murder but does not arrest the perpetrator. I'm not going to say why it seems to be okay to let her go - just in case you look it up. Many of the Columbo episodes are sentamental; but not many are tear jerkers.
Oh, by the way. The episode A Case for Immunity is also interesting. It is a testimony to our soft-bellied justice system compared to nations that think criminals are a waste of public resources - save for the cost of the bullet that gets them off the expense side of the public Profit and Loss sheet.