The First Law (Lescroart, John) by John Lescroart [Repost]

They date back to the wilder days of San Francisco's vigilante past, a private police force that keeps watch for paying clients. Unfortunately, Sam Silverman-an elderly pawnshop owner and a friend of Lt. Abe Glitsky's father-could no longer afford Patrol Special protection, and he may have paid with his life