Sidney Toler is Charlie Chan. Benson Fong is number three son Tommy and Willie Best is Chattanooga Brown, cousin of Birmingham Brown played by Mantan Moreland is a slew of previous movies. Charlie and company go to Mexico City to find out who stole papers describing how to make a super atomic bomb.
The papers were stolen from Alfred Wyans. His secretary Dorn is actually a detective working undercover for the U.S. He’s shot in front of witnesses. Before expiring he types out a few letters while everyone looks on. There was only one shot but two bullets fired. No gun is found.
Charlie is working with his old friend Inspector Luis Carvero (Fortunio Bonanova). Wyans had a number of guests over including an old flame of Luis’, Marguerite Fontan. Other guests include a gun runner , a smuggler and a singer. Tommy discovers a bottle of Red Dragon Chinese Ink on Dorn’s desk.
Wyans tells police that his typewriter has been stolen. Others head for the basement and search Wyan’s baggage. They don’t find anything but Charlie and Luis find the typewriter. Wyans tells them he’s figured out how Dorn was killed. That’s it for him. Same thing as Dorn and no gun has been found.
Charlie and everyone else visit the nightclub where Countess Irene is singing. In her dressing room she starts to let Charlie and company what’s going on and she’s bumped off the same way. Then an attempt is made on Charlie. Of course he figures it all out.
This is just an okay entry in the series. The murder method tries to be clever but ends up looking silly. There’s a good supply of comedy between Fong and Best. Some works. Some doesn’t. Not a big deal if you pass on this one.