SPOKANE, Wash. --- New court documents show the man killed in his Spokane Valley home feared his son so much that he installed a security camera system inside his house.

Police testified they believe the camera system likely captured the incident that left Huynh N. Bui, 61, dead inside his home near East Heroy Avenue and North McDonald Road.

The Spokane Medical Examiner’s Office reported on Wednesday Bui died from strangulation.

Seattle Police arrested the main suspect in the case on Tuesday night, Duy Bui-Nguyen.

Court records show Bui’s wife – and Bui-Nguyen’s stepmother – came home late from work Monday night. She told officers when she arrived at the house, her stepson came outside and “chased her off.”

She said Duy does drugs, and is “crazy.”

The stepmother said through a translator that she called her friend around 11:30 to tell him her stepson was confronting her, and then again just before midnight. They met at Trent and McDonald, the friend told police, and drove by her house several times and tried to call her husband’s cell phone, but it went straight to voicemail.

The friend eventually invited her to sleep at his business, and she left by 6 a.m. to go home, according to court records.

Bui-Nguyen’s stepmother called her friend again at 6:26 a.m. “in a panic,” and told him to call police.

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The court documents also showed Bui-Nguyen was taken to the hospital for a mental evaluation earlier this month on Nov. 7.

The staff of a Starbucks on Division asked an officer to remove Bui-Nguyen because he was acting strangely inside the business. The officer wrote in an incident report Bui-Nguyen was saying people were trying to kill him. Bui-Ngyen also said his mother was after him and trying to kill him. He resisted, but SPD officers were able to take him to Holy Family Medical Center for a mental evaluation.

As of Dec. 1, Bui-Nguyen was being held in King County Correctional Facility – Seattle on $1 million bond.

Duy Bui-Nguyen is now a suspect in a Spokane Valley homicide investigation.