The parents of Geoff Edwin Murphy allowed the troubled 33 year old to move back into their northwest Bakersfield home in late June.
A month later, police allege Murphy beat his father and then shot him to death.
Murphy pleaded not guilty Tuesday to four felonies, including murder. He's being held on $1.5 million bail with his next hearing scheduled for Oct. 23.
Bakersfield police reports filed in court say Murphy is bipolar, and had threatened his parents leading up to the Aug. 10 shooting. His behavior had become so unpredictable that his parents set up a video recorder in the living room that captured the moments before his father's death.
Murphy entered the living room and demanded his mother, Barbara Murphy, take him to a store, according to the reports. She refused, and Murphy became increasingly angry, threatening to "stomp her" to death and saying that he was in charge and she was a prisoner.
The reports say the son held a long lighter toward her and then hit her in the legs with it while continuing to make threats. Murphy's father, 74-year-old James Murphy, had seen enough.
The father stood up and pulled a handgun from his pocket, the reports say. Geoff Murphy looked at his father and mocked him.
James Murphy pulled the trigger. The bullet struck his son in the chest.
The reports say Geoff Murphy then rushed his father and knocked the frail, Parkinson's-suffering man to the ground. Geoff Murphy then beat him until he was no longer resisting, and fired a single shot into his head.
"Now you're dead, now you're dead, told ya," the reports say Geoff Murphy can be heard saying on the recording.
Geoff Murphy was arrested without incident and taken to Kern Medical Center for treatment of his gunshot wound. Detectives interviewed Murphy at the hospital and asked why he killed his father.
Murphy said his parents didn't respect him and treat him like an adult, the reports say. He said he had written up a list of rules he expected them to obey and had posted them on the door to his room.
The reports say Murphy told detectives that on the morning of the shooting he just wanted to go to a store but his mother was taking her time and he was tired of waiting. He said he yelled and said the things he did because he wanted the car keys, and his father overreacted. Murphy said he never would have followed through on his threats to "stomp" his mother.
Detectives asked Murphy what he would have done if someone kept threatening to kill his wife, but Murphy continued to make excuses for his behavior.
Barbara Murphy told detectives her son had been a smart child, but began to go downhill in high school and was diagnosed as bipolar, the reports say. She said he had received treatment and was on medication, and had later married a woman who was also bipolar.
Barbara Murphy said when she and her husband received word that Geoff Murphy -- with whom they'd had sporadic contact with after his marriage -- was getting divorced, they decided to offer him a place to stay. She said it didn't take long for her son's abusive side to emerge, and she and her husband applied for a restraining order against him just days before the shooting.
The reports say Barbara Murphy told detectives she struggled with her feelings regarding her son. She told them "you hate to think you could love someone this much and yet hate them for who they are."