Many years later , FBI profiler Robert K. Ressler said Mullin had paranoid schizophrenia , manifesting as early as his senior year of high school , and could have been accelerated by the use of LSD or amphetamines.Ressler , Robert K. and Tom Schachtman . '' Whoever Fights Monsters : My Twenty Years Hunting Serial Killers for the FBI . '' New York : St. Martin 's Press , 1992 , pp. 127-132 . By 1972 , Mullin was 25 and had moved back in with his parents in Felton , California ( located in the Santa Cruz Mountains ) . By now he was hearing voices in his head that told him an earthquake was imminent , and that only through human sacrifice could he save California . Mullin 's birthday , April 18 , was the anniversary of the 1906 San Francisco earthquake , which he thought was very significant
1906 San Francisco earthquake
1906 San Francisco earthquake
Herbert Mullin