Derek Connell, 29, is facing the death penalty after being accused of killing Scots mum Kim Higginbotham and her American husband Christopher in a bloody rampage.
The couple were found dead at their home in Bakersfield, California, on April 30 by police officers who were called to the scene.
Connell, originally from Glasgow, is also alleged to have taken a video of their dead bodies on his mobile phone and sent it to a relative.
He has denied the murders and claimed he arrived home to find his mother and stepfather already dead.
Police records state Mrs Higginbotham, 48, was found lying in a pool of blood in the hall of the property with a spent bullet near her body.
Mr Higginbotham, 48, was lying face down in a pool of blood and police said it appeared bleach had been poured on his skin and clothing in an effort to clean up.
Both were pronounced dead at the scene. Two shotguns, five handguns and seven rifles were seized from the home.
Connell was born in Rutherglen Maternity Hospital and lived with his mother in Shawlands on Glasgow’s south side as a child. No details of his father were listed on his birth certificate.
Mrs Higginbotham worked as a secretary in Glasgow and met her future husband while he was stationed with the US Navy in Scotland.
She moved with her son to be with Mr Higginbotham when he went back to America more than 20 years ago and the family settled in southern California.
Connell is being held in custody without bail while he awaits trial on two counts of first degree murder. Court documents state Connell told police he did not know what to do when he found the bodies and lay next to his mother face-to-face for an undetermined amount of time.
Connell said he tried to clean up the blood before he left the house and began driving around in circles. According to police, Connell said: “I probably didn’t handle the situation like I was supposed to. I had never had to deal with anything like that before.”
Connell also told officers that his stepfather had large gambling debts from betting on horse racing and boxing matches and had used a loan shark. Connell also claimed to have served in the US Army in Afghanistan and Iraq.
Mrs Higginbotham had worked for the last 16 years as a kindergarten teacher at the nearby Princeton Street Elementary School. A minute’s silence was held at the school following her death.
James Hay, director of student support services at Delano Union School District, said: “There was some intense grieving on the part of the staff. Mrs Higginbotham was a fixture at that school and was highly respected at that school. Her loss is going to be deeply felt.”
Her husband worked for Chevron Global Power at the Bakersfield Kern River Cogen, a co-generation power plant.
Neighbours in the quiet residential area told of their shock at the death of the couple.
Kim Riddle, whose children grew up with Connell, said the family moved into the neighbourhood when he was seven or eight.
She said “They were not real sociable but I guess they knew everybody because the group mailbox was right here in front of their house.
“When Derek came home from school, he had to do his homework right then and there and was not allowed to go out until it was all done. I did the same thing but after a while as my son got older, I was a little lax.”
Fellow neighbour Jana Owen said: “It really is a shock. I just feel so sad. Just to see them going out in body bags made me about want to vomit.”