In the thrilling finale of Charade (1963), when Brian Cruikshank (Cary Grant) sees Hamilton Bartholomew (Walter Matthau) and yells for Regina "Reggie" Lampert (Audrey Hepburn) to stop running, Cruikshank recognizes Bartholomew as Carson Dyle.
How did he know that was Carson Dyle? I don't recall any plot point that serves this recognition on Cruikshank's part.