Detective Kitty O'Day played by Jean Parker in the first of two films she did as Kitty O'Day who with her reluctant boyfriend Peter Cookson goes around solving crimes and generally getting into all kinds of mischief. If I didn't know any better I'd swear I was watching Bonita Granville and Frankie Thomas in one of the Warner Brothers Nancy Drew series albeit a bit older.
Parker is working for a millionaire who winds up dead with a widow who was already stepping out with Douglas Fowley. Veda Ann Borg was the merry widow and she's the main reason to see this as she usually is the main reason to see any film she's in.
Bodies start piling up in this 'mystery' until it is fairly obvious who could have done it.
One more film and there was no more demand for Kitty O'Day.