KINGSTON

Sarra Gilbert was hospitalized 10 times in the last three years for psychiatric issues before investigators said she fatally stabbed her mother in her Ellenville home — evidence key to her defense, her lawyer said in court Friday.

Gilbert, 27, pleaded not guilty in Ulster County Court to second-degree murder in the killing of her mother, Mari Gilbert. She was ordered held without bail.

“Sarra is, from all the evidence, clearly not responsible for what she’s done,” said her attorney John Ray, of Miller Place. “She’s what we call criminally insane. She’s a schizophrenic, a serious one. It’s extremely tragic for her, as well as for her mom, as well as her family.”

Gilbert has been in jail since the July 23 killing of Mari Gilbert, 52. The mother was a fierce advocate for another daughter, Shannan Gilbert, a sex worker whose disappearance led to the discovery of 10 sets of remains on Gilgo Beach. Police believe the killings may have been the work of one or more serial killers.

Shannan Gilbert’s body was found in Oak Beach in December 2011. Investigators eventually ruled that her death was unrelated to the serial murders.

Ellenville village police arrested Sarra Gilbert at the home — the scene of the killing — and reported recovering a 15-inch kitchen knife that is believed to have been used in the attack. She was indicted on the murder charge Tuesday.

At the arraignment, Ray said Gilbert underwent a psychiatric examination Thursday, as he had requested at an earlier court date, to determine if she is able to assist in her own defense. The results of that exam are expected before Gilbert’s next court hearing, scheduled Sept. 9.

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Ray told the judge he wants a psychiatrist to examine Sarra to support his defense that she was not responsible for her actions because of her mental condition, but that he hopes the district attorney’s office would request the exam so the state would pay for it.

Ulster County Judge Donald A. Williams responded incredulously: “That is your responsibility. . . . The court will not order an examination at the public’s expense to support an affirmative defense.”

In a separate criminal case, Sarra Gilbert was indicted in May on charges of endangering the welfare of a child, her 7-year-old son, and aggravated animal cruelty for the killing of her pit bull Princess, according to court documents.

Ray, who has said Shannan Gilbert’s death affected her sister’s mental health, added a new twist Friday, saying Mari Gilbert’s longtime practice of witchcraft also affected Sarra and he plans to use that as part of her defense.

“Mari was a lifetime practitioner of witchcraft and apparently of black magic,” Ray said. “And her children were adversely affected by it, there is no question about it whatsoever. Sarra suffered from terrible delusions about witches, about demons, about voices and such. How can one not connect that to what her mother was doing?”

Ray added: “Mari would have been in complete support of my defense. She loved her daughter, there’s no doubt of that whatsoever.”

Before the start of the hearing, which wasn’t attended by any Gilbert family members, Sarra Gilbert sat on a bench in the courthouse lobby in an orange jumpsuit, handcuffed and shackled, guarded by court officers.

Ray has previously said that Sarra Gilbert had stopped taking her prescription medicine prior to the stabbing.