The Ex Mrs. Bradford

The ExMrs. Bradford is a 1936 American comedymystery film. William Powell and Jean Arthur star as a divorced couple who investigate a murder at a racetrack. This was the last film directed by Stephen Roberts before his untimely death from a heart attack.

Then he receives an envelope addressed to North. North telephones a little later to say he will come pick it up. Curious, Brad opens the envelope to find a great deal of money. Someone claiming to be North calls shortly afterward and instructs Brad to meet him somewhere else, but without the money. Suspicious, Brad takes a taxi, but gets out a short distance away and returns to his suite. As he anticipated, a burglar is inside looking for the letter. When the two men start fighting, Paula tries to help, but ends up knocking Brad out instead, allowing the intruder to get away.Soon after, the doorbell rings. When Brad opens the door, Norths body falls in. Police Inspector Corrigan James Gleason names Brad as the main suspect in the second death. Now Brad has to solve both murders to clear himself. ........

Source: Wikipedia