A Darkness More Than Night by Michael Connelly

When a sheriff's detective shows up on former FBI man Terry McCaleb's Catalina Island doorstep and requests his help in analyzing photographs of a crime scene, McCaleb at first demurs. He's newly married (to Graciela, who herself dragged him from retirement into a case in Blood Work), has a new baby daughter, and is finally strong again after a heart transplant. But once a bloodhound, always a bloodhound. One look at the video of Edward Gunn's trussed and strangled body puts McCaleb back on the investigative trail, hooked by two details: the small statue of an owl that watches over the murder scene and the Latin words "Cave Cave Dus Videt," meaning "Beware, beware, God sees," on the tape binding the victim's mouth.