San Rafael woman charged with killing mother pleads insanity

A San Rafael woman charged with murdering her mother in January has changed her plea to not guilty by reason of insanity.

Tonantzyn Oris Beltran, 29, made the change during an appearance Thursday before Judge Geoffrey Howard in Marin County Superior Court. Beltran had originally pleaded not guilty without an insanity claim.

Howard ordered to be evaluated by psychiatrists to see if she meets the legal definition of insanity. He told Beltran that she potentially faces two trials, one on whether she committed the alleged crime and another on the sanity question. If she is found to be legally insane, she could be committed to a state hospital or a mental health treatment facility.

Beltran, sitting with defense attorney Matthew Siroka, calmly answered the judge’s questions during the proceeding. Howard set the next hearing for Dec. 12.

Siroka declined to comment on the case.

Beltran has been in no-bail custody at the Marin County Jail since Jan. 8, when San Rafael police arrested her after a standoff at an apartment complex on Cresta Way. She is accused of fatally stabbing her mother, Olivia Beltran, 55, who was a prominent community activist in Marin County.

Officers encountered Beltran standing with a knife in her hand on a balcony while her wounded mother lay next to her, police said. Police said Beltran broadcast the attack live on social media. Her mother died later at a hospital.