The Quick Red Fox: Travis McGee, Book 4 by John D. MacDonald

OK book, I would read the author again. PW: Travis McGee is looking for blackmailers for a superstar actress. With her personal secretary at his side, Mcgee is combing the country for suspects who attended a sex party with the sex symbol that produced pictures of all the participants. Trouble is, all of the other suspects show up in hospitals or dead.