My Late Wives by Carter Dickson

Roger Bewlay appeared to be a serial killer. He had married Angela Phipps, and a short time later, she disappeared. Two years later, he married Elizabeth Mosnar who later disappeared. Then he took up residence with Andree Cooper who had little money so they did not marry. She also disappeared. Bewley took different name for each of the women he was attached to so he was know as Roger Bewlay, Roger Bowdoin, and Richard Barclay. Chief Inspector Masters was in charge of the investigation but he never found Bewlay and he never found the women either. The police could not investigate any farther if there were no bodies. Then Mister R. Benedict and his wife moved to Torquay. One month later, R. Benedict left Torquay, and Mrs. Benedict disappeared. This time there was a witness who saw R. Benedict and his wife. Miss Lyons was a typist who had done some letters for Benedict, and he had paid her with a bad 10 shilling note. When she returned in the evening to get a good one, she saw the dead body of Mrs. Benedict on the couch through the window. Miss Lyons turned away and left. She told all this to Chief Inspector Masters who thought they would immediately find Roger Bewlay, but after ten years, the police still had not done so.

Now after 10 years, a new approach is taken to this story. Dennis Foster, a young lawyer, goes to see a play and to see his friend, the director, Beryl West. This play was due to close shortly, and the star of the play, the handsome actor Bruce Ransom, was planning to take a month off for rest and relaxation. However, Ransom had received a copy of a new play which seems to present a fictional version of the Roger Bewlay murders. Ransom would not reveal the name of the author. Beryl says that the ending is just not believable, and she does not want to present it. Ransom comes up with the idea of using his month off to go to a small village, pretend to be Roger Bewlay, and make love to a young woman. Beryl and Dennis tell this idea to Chief Inspector Masters and Sir Henry Merrivale. At first, Masters is opposed, but Sir Henry Merrivale says he will not help with the Bewley case unless Masters agrees to Ransom's imposture.

So now it really does get complicated. There are those who believe that Bruce Ransom is carrying out his plan to pretend to be Roger Bewlay, and there are those who believe that Bruce Ransom really is Roger Bewlay and has written the play himself. A dead body shows up and is carefully hidden in a place where people will look at it and not see it. Then there will be a rather dramatic ending which will really tell you who the real Roger Bewlay is.

This book was written in 1946 which makes it one of the later John Dickson Carr books.