Mr. Grim's Rabbits

Outside the Great Lakes Navigation Company a watchman sees a sailor carrying a package he claims is laundry. A minute later the sailor meets a man who greets him with the question 'Mr. Grim? ' To which he replies, 'Mr Grim's rabbits.' The man offers him $100, but when he demands more, he shoots him, runs away and ditches the package. Frank is called to the scene. When the body goes to the morgue an attendant hides the package with another corpse who is a John Doe. Meanwhile, importer R. Franklyn Matson III has a visit from a woman who expects him to deliver the package and who has $5000 for him. She thinks he has double crossed her, so she shoots him. Can Frank unravel what is going on?