I have now bought all dvd's up to season three. And here in Norway, season four has been airing this summer.

But the episode that I am looking for, was not one of them. I will try to explane.. It's an old lady that kills her nephew (I think)
She shuts him up in a big safe or closet, which is located in her office.

Does this make any sense at all? I think there is a matchstick (not sure of the spelling, in Norway we call it "fyrstikk")... And also some writing on the wall..

This is all I remember, I haven't seen this episode since the eighties..

-Try and catch me

But it's not her nephew, this guy killed Abigail Mitchell's nephew and old lady wants to revenge.You can find more info in section Episode Guides.

The episode you are asking about is called " Try and Catch Me " ( 1977 ) from the 7th season staring Ruth Gordon.
hbe

Thank you, both

Actually Vento, he ALLEGEDLY killed her NIECE, who was his wife. It's not established in the episode whether he actually killed her or not, but it's Abigails sucspicion or belief that he did that's the motivation for her murdering him.

Yes, you're right.You know if Columbo investigated the death of her niece, we would know exactly if he were murderer or not.

Yes, because we would have seen him do it!