CONCORD, CALIFORNIA – A Concord man accused of killing his elderly parents in a New Year’s Eve shooting has died while in custody at the Martinez Detention Facility, according to the Contra Costa County Sheriff’s Office. Officials say the death is now being investigated under the county’s law-enforcement fatal-incident protocol.
What officials say happened at the jail
In a statement attributed to the Contra Costa County Office of the Sheriff, officials said custody medical staff responded at about 5:38 a.m. Thursday, January 8, 2026 to a report that the inmate had suffered head injuries after “purposely banging his head” while housed in a cell.
The inmate was taken to a local hospital and medically cleared around 8:30 a.m., then transported back to the Martinez Detention Facility, where officials said he was uncooperative and later given medication by medical staff.
Later that day, at about 5:48 p.m., a deputy found the inmate unconscious in his cell, the sheriff’s statement said. Jail medical staff responded while deputies performed CPR, and fire/ambulance personnel also responded. The inmate was declared deceased, according to the statement.
Officials identified the inmate as Kirk Richardson, 61, of Concord, and said the Contra Costa County District Attorney’s Office is involved in the investigation.
What we know about the Concord killings
Richardson had been arrested in connection with a double homicide discovered the morning of Wednesday, December 31, 2025, after Concord police responded around 7 a.m. to a report of a “family disturbance” at a home in the 3900 block of Walnut Avenue (near Clayton Way, according to one report). Police found two people dead from apparent gunshot wounds.
KTVU and NBC Bay Area reported the victims were Richardson’s parents, William Richardson, 90, and Joyce Richardson, 85, and that prosecutors filed two murder counts with firearm enhancements. He had been held on $4 million bail, according to KTVU’s earlier report.
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What happens next
KTVU reported the Contra Costa County District Attorney’s Office investigates deaths that occur during encounters with law enforcement, and the sheriff’s office statement said the countywide fatal-incident protocol was invoked. The official cause of death has not yet been determined in the public reporting.
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Read Next
If you’re catching up on this case, start with our earlier coverage, “New Details Revealed About Double Murder in Concord, as Son Allegedly Slayed Both Parents”. We also have recent Contra Costa safety coverage including “Cashier Shot Over a Matter of Cigarettes in Walnut Creek” and “‘Armed and Dangerous’: Police Identify Suspect Who Allegedly Shot 11-Year-Old Girl in the Head in Antioch”.
