In April 1987, Purdy and his half-brother Albert were arrested for firing a semi-automatic pistol at trees in the Eldorado National Forest. At the time, he was carrying a book about the white supremacist group Aryan Nations. He told the County Sheriff that it was his "duty to help the suppressed and overthrow the suppressor." In prison, he twice attempted suicide, once by hanging himself with a rope made out of strips of his shirt, and a second time by cutting his wrists with his fingernails. A subsequent psychiatric assessment found him to suffer from very mild mental retardation, and to be a danger to himself and others.