Eric Ambler is mostly known as a writer of spy related novels. Mask of Dimitrios (published in the U.S. as A Coffin for Dimitrios)
is about a writer of detective stories who bargains for more than he
can handle as he researches the mysterious Dimitrios. He is pulled
farther and farther into a web of deceit. The book was made into a film
and the film into a radio play as presented on the Screen Guild Theatre in 1945.
A look at the story and Ambler.