Currently Watching - The Thin Man Goes Home (1944)

This is one of my favorite of the Thin Man movies.

Nick and Nora's visit Nick's parents in Nick's hometown of Sycamore Springs. The residents are convinced that Nick is in town on an investigation, despite Nick's repeated denials. However, when aircraft factory employee Peter Berton seeks out Nick and is shot dead before he can reveal anything, Nick is on the case.
An old childhood friend, Dr. Bruce Clayworth, performs the autopsy and extracts a pistol bullet. Then, when Nick searches Berton's room for clues, he is knocked unconscious by Crazy Mary, a local eccentric.
Nora's innocent purchase of an old painting for Nick's birthday present turns out to be the key to the mystery. When she shows it to her husband, it brings back unpleasant memories for him, so she donates it to a charity bazaar. When Edgar Draque offers Nora a large sum for the painting, Nick wonders why it is so valuable. Nick learns that Draque's wife Helena bought the artwork, but she is knocked out and the painting goes missing. Nick discovers that Crazy Mary is Berton's mother and goes to see her, only to come across her lifeless body. Nick and Nora's dog Asta finds the painting in her shack.
Nick puts the pieces together and has the police bring all the suspects to his father's house. (Early on, it is revealed that Nick's father, Dr. Bertram Charles, has never been overly impressed with his son's unusual career choice, so this gives Nick an opportunity to change his father's mind.) Using Dr. Charles's fluoroscope, Nick shows that there is a blueprint hidden underneath the paint. Several people identify it as part of the specifications for a new aircraft propeller worth a great deal to a "foreign power". Berton had copied the blueprints and smuggled them out in five paintings. He had a change of heart and was going to confess all to Nick, but was killed before he could. Nick has a souvenir World War II Japanese sniper rifle belonging to Dr. Clayworth's brother brought in, and claims it was the murder weapon. Then, after proving that the Draques are members of the crime ring, Nick reveals the identity of the leader of the gang: Dr. Bruce Clayworth. Clayworth's first slip was the bullet he showed Nick. Nick knew a pistol did not have the power to propel a bullet as far into Berton's body as the real one had. Clayworth grabs the rifle and, after confessing (and also revealing a deep hatred for Nick for always being better than him in their youth), tries to shoot his nemesis, only to find that Nick had taken the precaution of having the firing pin removed. Nick's father is very impressed.