Shortly after 2 a.m. on April 6, 2010, a guard at Salinas Valley State Prison noticed Alan Ager's cellmate trying to stuff something under a mattress. It was Ager, blood trickling from his mouth and a cloth noose tied around his neck. The convicted child molester died 10 days later without regaining consciousness, his death earning his cellmate a second life sentence. California state prisoners are killed at a rate that is double the national average — and sex offenders like Ager account for a disproportionate number of victims, according to an Associated Press analysis of corrections records.