A 61-year-old man accused in the December 31 killings of his elderly parents in Concord was found dead in his jail cell Thursday evening.

Kirk Laroy Richardson, who was arrested last week and charged with the New Year's Eve murders of his parents, was found dead Thursday in his cell at the Martinez Detention Facility after apparently inflicting fatal injuries upon himself.

According to the Contra Costa County Sheriff's Office, Richardson, who had been in custody at the Martinez jail for eight days, since December 31, first attempted to seriously injure himself early Thursday morning. Medical staff were called to his cell at 5:38 am after a report of "head injuries that an inmate apparently sustained as a result of him purposely banging his head."

A fire department ambulance transported Richardson to a local hospital, where he was treated for his injuries. Richardson was medically cleared as of 8:30 am Thursday and transported back to the jail, where he was given medication.

A sheriff's deputy then found Richardson unresponsive in his cell around 5:48 pm that evening. "Jail medical staff responded while deputies performed CPR," the sheriff's office writes.

Richardson was pronounced dead at the scene.

As per protocol, the Contra Costa District Attorney’s Office and the sheriff's office are jointly investigating the in-custody death.

Richardson was arrested after a report of a "family disturbance" was called in around 7 am on December 31, and the Richardsons' home on Walnut Avenue.

As KRON4 reported, following the arrest, Richardson was known to neighbors as a frightening figure with a history of drug use and mental health issues.

Two neighbors, a couple, filed restraining orders against Richardson over 12 years ago, in 2013. According to documents at the time, one member of the couple had backed out of a fishing trip he had planned with Richardson, and he said Richardson then "threatened to decapitate me and put my guts in a trash bag."

The neighbor described Richardson as "extremely violent" and said he was "in the mental health system."

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