1940’s-ish movie wife escaped husband by wiring library so he would be electrocuted

1940’s-ish movie where wife escaped vile husband by wiring the library so if he tried to get out he would be electrocuted. It was shown on one of those creature feature shows on channel 9 or 11 in NYC sometime during the late 60’s early 70’s

I think it opened with real estate people telling perspective buyers the history of the house.