In the novel The Body in the Library, Mike Carmody was the first husband of Adelaide Jefferson and the father of Peter. He died before his son was born. He was a good friend of Frank Jefferson, and wanted Frank to be Peter's godfather.
Mike Carmody does not appear in either the BBC 1984 adaptation of the novel or the ITV 2004 adaptation. In the latter, he is mentioned as a fellow R.A.F. fighter pilot and friend of Frank Jefferson and Mark Gaskell. Mike was killed during the war and Mark then married his widow Adelaide.