Mr. Arkadin (aka Confidential Report, 1955).

Orson Welles in Amsterdam,
1952. Photo by Harry Pot.
Anefo, Dutch Nat Archives

Starring, written, and directed by Orson Welles, Mr. Arkadin features a confidence man looking into the shrouded past of a millionaire, as key witnesses are bumped off. The film costars Michael Redgrave, Patricia Medina, and Mischa Auer. It has a somewhat torturous history, with incarnations that include radio plays, deleted scenes, and a European version called Confidential Report.