Mystery Street (1950)

Mystery Street (1950): written by Sydney Boehm, Richard Brooks, and Leonard Spigelgass; directed by John Sturges; starring Ricardo Montalban (Det. Morales), Sally Forrest (Grace Shanway), Bruce Bennett (Dr. McAdoo), Elsa Lanchester (Mrs. Smerling), Marshall Thompson (Henry Shanway), and Jan Sterling (Vivian Heldon): Solid noir procedural has some nice visual touches. It's a fairly ground-breaking movie for two reasons. For one, Ricardo Montalban gets to play a police detective after generally playing Latino Lotharios in his previous American work. And he's very good as that detective -- one wishes he'd gotten more roles like this. 

The second reason would be that Mystery Street's crime-solving detectives get a lot of help from a forensics expert at Harvard University. One is basically witnessing the birth of the CSI genre, with Montalban's detective slowly being sold on the expert's value to this investigation and many investigations to come. Like a crazy cherry on top comes Elsa Lanchester as a seemingly dotty, secretly malign landlady. Really a hidden gem of a movie. Recommended.