The Avenging Hand (aka Paradise Hotel)

Chicago mobster Lee Barwell on holiday in London feels right at home when he finds himself in the middle of a blazing downtown shoot-out by rival English gangs. During the melee, Lee recovers a note explaining that four gangsters plan to meet at the Paradise Hotel and split up a million dollars in stolen cash. He trails them to the hotel, but when one of the conspirators is murdered and no one can find the loot, the vacationing boss decides to take a turn as a detective, and solve the mystery.