Adventure in Diamonds

Adventure in Diamonds is a 1940 American crime film directed by George Fitzmaurice and starring George Brent, Isa Miranda, John Loder and Nigel Bruce. It was also released as Diamonds are Dangerous.

The Captain isnt that easily fooled though, and with his own agenda, he ends up with the stolen jewels himself. He decides to frame the two thieves, and makes contact with his acquaintance, the police commissioner Colonel J.W. Lansfield. He turns the jewels over to the Colonel, who has been set on catching Barclay for a long time, and he sets a trap with the diamond jewels. However, the plan backfires, and Felice is caught in the trap instead of Barclay. She is sentenced to prison, but is offered a parole by the Colonel if she agrees to help out catching a new ring of jewel thieves operating in the area. She is to pretend to be Stephens new wife, and the two of them are supposed to deliver the stolen jewels to the new gang.While they wait to be contacted by the gang, Felice and Stephen spend some quality time together, and Felice falls in love with Stephen for real. She decides to renounce her criminal past and start anew. When the gang eventually make contact, it turns out that the leader is Felices old accomplice Barclay, and their cover is instantly blown. They have to be rescued by the colonel and his men, but Felice is permanently out of prison and can start her new life with Stephen. ........

Source: Wikipedia