We Chase Shadows by Richard Osman
This is the newest in the We Solve Murders series featuring writer Rosie, retired cop Steve, and his daughter in law Amy, who was a protection officer. They get hired by Vern Blackwood, a millionaire of shifty reputation, whose bodyguard was killed at his villa in Italy and found with a note saying a mysery man named Erickson is responsible. Vern hires the We Solve Murders crew to track down Erickson, who he declares could not be responsible for the death. The story is told with a sense of humor and some satisfying plot twists. I can't wait to see what this gang is up to next.