CONTRA COSTA COUNTY (CBS SF) — In Contra Costa County, a coroner’s jury on Friday released its findings into the death of Angelo Quinto, a man who died while in police custody late last year.

Quinto died three days after a struggle with Antioch police, who forcibly held him down during a mental health crisis.

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Authorities say the 30-year-old was acting aggressively towards his mother when one of his sisters, Cassandra Collins, called police on December 23rd. Police restrained Angelo – but the family alleges officers had their knee on his neck for several minutes.

Antioch police say they only had a knee on his shoulder blade for a few seconds while handcuffing him.

On Friday, the coroner’s inquest jury unanimously ruled Quinto’s death as accidental. His death was blamed on “excited delirium,” a state attributed to a narcolepsy drug found in Quinto’s system.

It’s a controversial diagnosis which the American Medical Association denounced in June, saying it is commonly used to justify excessive force by officers.

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Family members say his death could have been avoided.

“It’s extremely disappointing,” said his sister, Isabella Quinto-Collins. “It’s extremely painful and it’s extremely constant…[we will] not stop fighting for what we believe in and what my brother deserves.”

“It’s really a bogus argument. We’ve had many cases and each time it has been debunked,” said the family’s attorney John Burris.

Earlier this month, Quinto’s mother and younger sister filed a lawsuit seeking unspecified monetary damages and alleging Antioch Police officers used excessive force when restraining him.

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The suit names the city, Antioch Police Chief Tammany Brooks and Officers James Perkinson, Arturo Becerra, Daniel Hopwood and Nicholas Shipilov.