Cat Pay the Devil is the 12th book in the Joe Grey mystery/fantasy series. I've read all but one and intend to do soon.
Molena Point, California, on the Pacific coast, is not a place where most escaped federal prisoners would hole up. Cage Jones, a federal prisoner, escapes and does just that. He is out for revenge against a resident of that town, Wilma Getz,
his ex probation officer, who testified against him. He also thinks she has stolen a hidden fortune from him.
This is where the fantasy part of the mystery comes in. Wilma's cat, Dulcie learns of of his escape and fears for Wilma. Joe Grey, her cat friend, is puzzling over over two murders and doesn't pay attention to Dulcie's fear until Dulcie finds Cage in Wilma's house ransacking it and Wilma is reported missing.
Along with Kit, the three indomitable felines, paw-in-hand with the unsuspecting cops—and with special powers known by only a few select humans—help untangle Jones' agenda and the brutal murders. I think this is one of Murphy's most suspenseful books. It is an imaginative trip into the hidden lives of felines—the cats named above, and a band of feral friends, as they help solve the mysteries.