Born in Burbank, California, Kemper had a troubled upbringing. His parents divorced in early life; as a child, he moved to Montana with his abusive mother Clarnell, who locked Kemper in their basement which had been frequented by rats. He ran away to reunite with his father, but was left behind in North Fork, California on Christmas Day in 1963, where he murdered his paternal grandparents when he was 15. Following the murders, he was briefly diagnosed with paranoid schizophrenia by court psychiatrists and sentenced to the Atascadero State Hospital as a criminally insane juvenile. Edmund Emil Kemper III was born in Burbank, California, on December 18, 1948. He was the middle child and only son born to Clarnell Elizabeth Kemper (née Stage, 1921–1973) and Edmund Emil Kemper Jr. (1917–1985). Edmund Jr. was a World War II veteran who, after the war, tested nuclear weapons in the Pacific Proving Grounds before returning to California, where he worked as an electrician. Clarnell often complained about Edmund II's "menial" electrician job, and he later said "suicide missions in wartime and the atomic bomb testings were nothing compared to living with her" and that Clarnell affected him "more than three hundred and ninety-six days and nights of fighting on the front did."Weighing 13 pounds (5.9 kg) as a newborn, Kemper was a head taller than his peers by the age of four. Early on, he exhibited antisocial behavior such as cruelty to animals: At the age of 10, he buried a pet cat alive; once it died, he dug it up, decapitated it, and mounted its head on a spike. Kemper later stated that he derived pleasure from successfully lying to his family about killing the cat. At the age of 13, he killed another family cat when he perceived it to be favoring his younger sister, Allyn Lee Kemper (born 1951), over him; and he kept pieces of it in his closet until his mother found them. Kemper had a dark fantasy life. He performed rites with his younger sister's dolls that culminated in his removing their heads and hands; on one occasion, when his elder sister, Susan Hughey Kemper (1943–2014), teased him and asked why he did not try to kiss his teacher, he replied, "If I kiss her, I'd have to kill her first." He also recalled that as a young boy, he would sneak out of his house and, armed with his father's bayonet, go to his second-grade teacher's house to watch her through the windows. He stated in later interviews that some of his favorite games to play as a child were "Gas Chamber" and "Electric Chair," in which he asked his younger sister to tie him up and flip an imaginary switch; he would then tumble over and writhe on the floor, pretending that he was being executed by gas inhalation or electric shock. He also had close-to-death experiences as a child: once, when his elder sister tried to push him in front of a train and another time when she successfully pushed him into the deep end of a swimming pool, where he almost drowned. Kemper had a close relationship with his father and was devastated when his parents separated in 1957, causing him to be raised by Clarnell in Helena, Montana. He had a severely dysfunctional relationship with his mother, a neurotic, domineering alcoholic who frequently belittled, humiliated, and abused him. Clarnell often made her son sleep in a locked basement because she feared that he would harm his sisters, regularly mocked him for his large size—he stood 6 feet 4 inches (1.93 m) by the age of 15—and derided him as "a real weirdo." She also refused to show him affection out of fear that she would "turn him gay" and told the young Kemper that he reminded her of his father and that no woman would ever love him. Kemper later described her as a "sick angry woman," and it has been postulated that she suffered from borderline personality disorder. At the age of 14, Kemper ran away from home in an attempt to reconcile with his father in Van Nuys, California. Once there, he learned that his father had remarried and had a stepson. Kemper stayed with his father for a short while until the elder Kemper sent him to live with his paternal grandparents, who lived on a ranch in the mountains of North Fork, California. Kemper hated living in North Fork; he described his grandfather as "senile" and said that his grandmother "was constantly emasculating me and my grandfather."