Clandestine by James Ellroy
Los Angeles 1951 - Frederick Underhill, an ambitious rookie of the Los Angeles Police Department, want to become the most celebrated detective of his time. He is also sexually promiscuous. His two drives are brought together by the slaying of Maggie Cadwallader, a lonely woman whom Underhill slept with shortly before her death.
Using his inside knowledge, Underhill gets himself on the case, which is being handled by LA's most fearsome investigator: Lieutenant Dudley Smith. But instead of the celebrity status he was hoping for, Underhill finds himself on the edge of the abyss, his whole life and future about to take a fall.