Because the Night - James Ellroy

A botched liquor store heist leaves three grisly dead. A hero cop is missing. Nobody could see a pattern in these two stray bits of information-no one except Detective Sergeant Lloyd Hopkins, a brilliant and disturbed L.A. cop with an obsessive desire to protect the innocent. To him they lead to one horrifying conclusion--a killer is on the loose and preying on his city. From the master of L.A. noir comes this beautiful and brutal tale of a cop and a criminal squared off in a life and death struggle.