Unnatural Causes (1993)

Roy Marsden returns as author P.D. James's indefatigable gumshoe, Inspector Adam Dalgliesh. This time, he's investigating the murder of a famous mystery writer whose body is found in the bottom of a dinghy on the Suffolk coast. To add a further degree of difficulty, Dalgliesh must contend with a colleague on the case, the aptly named Inspector Reckless.