In March 1949, Joe DiMaggio posed in Yankee Stadium, smiling, with another famous Italian-American of his era — each in his professional uniform — but their friendship would not endure.

On the evening of Nov. 5, 1954, the Yankee Clipper and Frank Sinatra hastily got up from dinner with friends at the Villa Capri in Hollywood and drove to a little apartment house at Kilkea Drive and Waring Avenue. DiMaggio was being divorced by Marilyn Monroe, his wife of less than a year. A private investigator, Barney Ruditsky, had called to report that she was there with another man.

When a door was kicked in on one of the apartments — we still do not know exactly who did the deed — the intruders, one using a flash camera, found not Monroe but a shrieking office secretary, Florence Kotz, in her nightgown. (She later sued DiMaggio, Sinatra, Ruditsky and three others she identified as their confederates, and got $7,500 in an out-of-court settlement brokered by Sinatra’s lawyer.) In later testimony before a California state senate panel examining the ethics of private investigators, Ms. Kotz’s landlady, Virginia Blasgen, recalled seeing, from her window, DiMaggio and Sinatra outside the building, arguing. She said Sinatra appeared animated but amused — he was “jumping up and down and looking at me, smiling” — but DiMaggio simply looked “mad.”

Americans learned about what came to be called the “Wrong-Door Raid” when Confidential magazine revealed it two years later. Furious and embarrassed (even though Sinatra had ostensibly been trying to help him), DiMaggio scarcely spoke to Sinatra afterward.