Purdy's mother remarried in September 1969; she divorced her husband four years later. Albert Gulart, Sr., Purdy's stepfather, said Purdy was an overly quiet child who cried often. In fall 1973, Kathleen separated from Gulart and moved with her children from Stockton to the Sacramento area. In December of that year, the Sacramento Child Protective Services were twice called to her residence, on allegations that Kathleen was physically abusing her children. When Purdy was thirteen, he struck his mother in the face and was permanently banned from her house. He lived on the streets of San Francisco for a period before being placed in foster care by authorities. He was later placed in the custody of his father, who was living in Lodi, California, at the time. While attending Lodi High School, Purdy became an alcoholic and a drug addict, and attended high school sporadically.