(Crime) China Passage - Constance Worth, Vinton Hayworth, Leslie Fenton 1937

https://www.imdb.com/title/tt0028715/ Tommy Baldwin and Joe Dugan are entrusted to carry a fabulous diamond. If they succeed, they will be well paid. If they fail, they will be well buried. When they go to pick up the diamond, there is a great gun battle, a cannister of knock out gas, and the diamond is stolen.