This is the 262nd in my series of forgotten or seldom read books
A Six-Letter Word For Death by Patricia Moyes, Henry Holt (an Owl Book) 1985 mass market paperback
This is the 17th in the series, and takes place on the Isle of Wight. Henry has been invited to speak to a small group of authors on Scotland Yard CID procedures, and has a successful talk. Before he arrived, Tibbett had been sent a crossword puzzle to solve, and it turns out that the solution included the names of the authors and other information which the group intended Tibbett to solve, or, embarrassingly, fail to solve. Thus the books titular reference to crossword.
The crossword hints at foul play in past deaths, each clue referencing one of the six authors in the group. The mystery writers all use pen names, keeping their identities secret, but Henry has little difficulty deducing who they are. He presents his police procedure talk, then reveals he solved the crossword, knew which writer designed it, and has investigated the events referenced by crossword clues.
One of the guests makes an appointment, heard by all, to see Henry later in the afternoon but then dies of an apparent accidental death before he can keep it. Henry is suspicious, and does his own unofficial investigation. When the crime scene and evidence are tampered with, Henry is certain the death was no accident.
He and Emmy extend their vacation, in order to remain in the area and keep investigating. He ultimately stages a re-enactment of a decades-old crime to resolve all mysteries and obtain justice.
Though I found the plot in this one to be more convoluted than usual, I was happy with the conclusion, and as always Henry and Emmy are delightful. Well worth reading