In honor of today being the anniversary of Peter Lorre's death I declared a 1-day Lorre Blogathon. I've linked my posts on Peter Lorre's films here.
Mr. Moto's Last Warning is a 1939 film, 6th in a series of Mr. Moto films starring Peter Lorre. John Carradine and George Sanders (another favorite around here) are also in this one.
The Internet Archive has it online:
You can also see it online at Joost.
TCM has a page with some basic information.