The word is murder

"One bright sping morning in London, Diana Cowper, the wealthy mother of a famous actor, enters a funeral parlor. She is there to plan her own service. Six hours later she is found dead in her own home, strangled with a curtain cord. Enter disgraced police detective Daniel Hawthorne, a brilliant, eccentric investigator who is as quick with an insult as he is to crack a case. Hawthorne needs a ghostwriter to document his life, a Watson to his Holmes. He chooses Anthony Horowitz. Drawn in against his will, Horowitz soon finds himself at the center of a story he cannot control. Hawthorne is brusque, tempermental, and annoying; but even so, his latest case, with its many twists and turns, proves irresistible. The writer and the detective form an unusual partnership. But it soon becomes clear that Hawthorne is hiding some dark secrets of his own."--Dust jacket.