Spider Woman’s Daughter by Anne Hillerman

When a retired colleague is gunned down just after a breakfast meeting Navajo Nation Police Officer Bernadette Manualito is shocked by the boldness and sheer cold-bloodedness of the act. What is worse is that the retired officer is a close friend both to her and to her husband Sergeant Jim Chee.
An officer known to the Navajo Nation Police as “the Legendary Lieutenant” is bound to have his share of enemies, but who would bear a grudge that strong to gun him down in broad daylight in the parking lot of a crowded restaurant full of police officers?
As a witness, Officer Manualito is forbidden by regulation to be involved in the case, but neither she is going to sit idly by and do nothing. But the identity of the shooter and the reason for the shooting are unclear, tangled up in a web of cold cases and an unfinished private investigation into the insurance value of a private collection of ancient Native American artifacts. A web as tangled as any woven by Spider Woman herself.