Perry Mason: The Case of the Scandalous Scoundrel (1987)

Perry is suing a gutter-trash newspaper that is running a story about a love affair between him and Della. The editor also has "dirt" files on an Army General, his banker, and other "clients". All of them make little-concealed verbal threats to him at a party, but the person who hated him most is a female reporter the editor had just fired from the paper for attempting to write a serious story. Soon after she threatens him, he's found floating in his pool, shot. The reporter is arrested for the crime and Perry, who has a personal stake in the matter, sets out with Della and Paul to solve the mystery. But the other suspects just want the case to be over and will go to any lengths to protect their secrets.