Justice by Faye Kellerman

The cruel and bizarre slaying of a beautiful teen leads Detective Decker into the dark heart of an exotic subculture: the seamy, sometimes violent world of Southern California's rootless, affluent youth. But even the confession of a disturbed kid with cold "killer eyes" cannot soothe Decker's inner torment. For he knows in his gut this crime goes much deeper and higher than anyone expects -- and that true justice, brutal and complete, has yet to be done.