Charlie Chan in Panama

Charlie Chan in Panama is a 1940 mystery film starring Sidney Toler. It is an unaccredited remake of Jacques Devals novel Marie Galante, produced by Fox Film Corporation in 1934, directed by Henry King.

As the other suspects are murdered, one by one, first Compton, then Manolo, Chan learns that the canals Miraflores locks are to be blown up at ten that night. Chan then sequesters the suspects at the plant, forcing Miss Finch to expose herself as Reiner in order to escape death. With Reiner under arrest, the fleet sails safely through the locks to protect democracy.

Source: Wikipedia