The Fatal Hour (1940) starring Boris Karloff as Mr Wong

When a police officer is murdered, Captain Street looks to Mr. Wong (Karloff) to catch the killer. Prime Suspect: Frank Belden Jr., whose father is a businessman well known for both his success and dishonesty. Mr. Wong faces increasing danger and is nearly executed himself as the investigation develops in treachery and complexity. Grant Withers as Capt. Bill Street
Marjorie Reynolds as Roberta 'Bobbie' Logan. Fourth installation of the series, the film is also known as Mr. Wong at Headquarters in the United Kingdom. The picture was followed by the sequel Doomed to Die, which also stars Karloff, Reynolds and Withers.