Swift vengeance / T. Jefferson Parker.

Returning hero and private investigator Roland Ford is on the trail of a mysterious killer who is beheading CIA drone operators and leaving puzzling clues at each crime scene. His troubled friend Lindsay Rakes is afraid for her own life and the life of her son after a fellow flight crew member is killed in brutal fashion. Even more terrifying is the odd note the killer left behind: "Welcome to Caliphornia. This is not the last." Ford strikes an uneasy alliance with San Diego-based FBI agent Joan Taucher, who is tough as nails but haunted by what sees as the Bureau's failure to catch the 9/11 terrorists, many of whom spent their last days in her city. As the killer strikes again, Ford and Taucher dash into the fray, each desperate for their own reasons--each ready to risk it all to stop the killer from doing far more damage.