Sarra Elizabeth Gilbert Case: Insanity Defense, Sentence, Appeal

Sarra Elizabeth Gilbert is serving 25 years to life in a New York state prison for the July 2016 stabbing death of her mother, Mari Gilbert, the Long Island woman who spent years pressuring police to investigate her older daughter Shannan’s disappearance as part of the Gilgo Beach serial killer case. In the Sarra Gilbert case, a Ulster County jury rejected an insanity defense built on her documented schizophrenia and found her guilty of second-degree murder in April 2017. A state appellate court unanimously upheld the conviction in November 2021.

What Happened on July 23, 2016

Police in Ellenville, New York, went to Mari Gilbert’s apartment that afternoon for a welfare check after her daughter Sherre called worried about her mother. Officers saw Mari’s body through a window before going inside, where they found 27-year-old Sarra in the kitchen covered in blood. A knife was recovered at the scene, and Sarra was detained immediately.¹

Prosecutors later established that Sarra stabbed her mother more than 227 times with a 15-inch kitchen knife, struck her with a fire extinguisher, sprayed extinguisher foam into her mouth, and attempted to decapitate her.²³ She was arraigned on charges of second-degree murder and criminal possession of a weapon and held without bail at the Ulster County Jail.⁴

Sarra’s Mental Illness and Prior Arrests

Sarra was diagnosed with schizophrenia in early 2014 and had been hospitalized at least ten times in the three years before the killing, most recently in June 2016.⁵ Her sister Sherre wrote on social media that the family “tried to get Sarra help many times since she was diagnosed with schizophrenia in early 2014 and she would get better and then her condition would get worse.”⁶

In February 2016, Sarra was arrested on charges of animal cruelty and endangering the welfare of a child after she allegedly drowned a puppy in a bathtub in front of her eight-year-old son and then took the boy into the woods and threatened to kill him. She was arrested again in May 2016 for criminal contempt after violating an order of protection obtained by her boyfriend.⁷ Both cases were still pending when she killed her mother. After Mari had Sarra arrested over the puppy incident, Mari gained custody of Sarra’s son. Family attorney John Ray said Sarra had stopped taking her prescribed medication in the days before the killing and had begun hearing voices again.⁵

The Insanity Defense at Trial

The trial was held in Ulster County Court before Judge Donald Williams, with Assistant District Attorney Emmanuel Nneji prosecuting and John Ray defending. Ray had previously represented Mari Gilbert in civil litigation over Shannan’s death and was asked to defend Sarra after the murder.⁷

The defense raised the affirmative defense of lack of criminal responsibility by reason of mental disease or defect under New York Penal Law § 40.15. Ray argued that Sarra’s schizophrenia rendered her unable to understand the nature and consequences of her actions or that they were wrong, and that she killed her mother believing Mari was possessed by a demon.⁸ Ray also told the court that Mari had “dabbled in the occult since she was 17 years old” and that this had “adversely affected” her children, feeding Sarra’s psychotic beliefs.⁹

The Battle of the Experts

The case turned on two competing psychiatrists. Forensic psychologist Alexander Bardey testified for the defense that Sarra had acute schizophrenia at the time of the killing, that her medication regimen had been interrupted when she missed her scheduled July 2016 injections, and that her psychosis worsened as a result. He described her hallucinations of green lights, cars on walls, and rain inside her apartment, along with delusions that she was God-like and chosen to fight the devil. Bardey concluded that Sarra “lacked the substantial capacity to understand the nature and consequences of her actions or that they were wrong” and believed she was “killing a demon rather than her mother.”⁸ On cross-examination, he conceded that Sarra “maintained an ability to lie, even if she was psychotic.”¹⁰

Psychiatrist Sandra Antoniak testified for the prosecution. She had interviewed Sarra twice and reviewed her medical records and body camera footage. Antoniak administered the Miller’s Forensic Assessment of Symptoms Test, on which Sarra scored a 5, a result Antoniak said indicated with “97% accuracy” that the defendant was malingering. Antoniak acknowledged that Sarra had a mental illness (described at points as schizoaffective disorder) but concluded her conduct was driven more by drug abuse than by illness, and that she had a rational motive: resentment toward her mother for having her arrested and taking custody of her son after the puppy incident.¹¹ Antoniak testified that Sarra told her she had stabbed her mother in the upper chest “over the heart because she knew that that would be the most lethal place to stab her” and that she “wanted her dead.” After the killing, Sarra removed her blood-soaked jogging pants, went into the bathroom, and washed her hands.¹²

Sarra’s Own Statements and the Verdict

Sarra took the stand and testified that she intended to kill her mother, calling the victim an “evil God” who “deserved to die.” She admitted stopping to smoke a cigarette during the attack and removing her mother’s clothing because she believed the clothes “gave her more power.”¹³ The jury saw body camera footage of Sarra telling officers “I killed my mom” and “I am under arrest,” and heard a recorded interview in which she said she “murdered my mother” to stop the “voices.” A journal she kept, with entries about “demon eyes,” witchcraft, and her self-identification as “God,” was also entered into evidence.¹²

On April 27, 2017, the jury rejected the insanity defense and found Sarra Gilbert guilty of second-degree murder.²

The 25-to-Life Sentence

Judge Williams sentenced Sarra on August 4, 2017, to 25 years to life in state prison, the maximum allowed by law. He called the crime “intentional, premeditated and planned” and said the sentence was driven by “an overwhelming desire to protect other people by taking you off the streets for as long as I can.”¹⁴

A letter from Sarra’s sister Stevie Smith, read in court by the prosecutor, called Sarra “wicked” and said the killing was “not a result of mental illness” but “the result of long term hate.” Ray, in a striking moment, described his own client as “insane, violent, psychotic, and repeatedly homicidal” and warned “she will kill again.” Prosecutor Nneji argued the danger came from sociopathy rather than mental illness.² Judge Williams said he would “never be able to put out of my mind” those warnings.¹⁵

Sarra sobbed and asked for mercy when given the chance to speak. After sentencing, the District Attorney’s Office dropped the pending animal cruelty and child endangerment charges.¹⁴

The 2021 Appeal

The Appellate Division of the New York Supreme Court, Third Department, unanimously affirmed the conviction on November 4, 2021.⁸ Sarra had argued that the evidence was legally insufficient to overcome her insanity defense, that Antoniak was unqualified to testify as an expert, and that the trial court had failed to formally certify Antoniak as an expert on the record.

The five-judge panel rejected each argument. On the insanity defense, the court held that when experts disagree the jury decides, and that the prosecution had presented ample independent evidence of Sarra’s awareness of her actions, including her statements that she “felt bad” afterward, her agreement that the stabbing would have been wrong even without the voices, and her efforts to conceal what she had done.⁸ The court also held that a trial judge is not required to formally certify a witness as an expert on the record.¹²

The Gilgo Beach Connection

The case drew national attention because of who the victim was. Mari Gilbert’s older daughter, Shannan Gilbert, was a 23-year-old escort who vanished on May 1, 2010, after making a frantic 911 call from a client’s home in Oak Beach, Long Island. The search for Shannan led police to discover four sets of remains along Ocean Parkway near Gilgo Beach in December 2010, and eventually ten sets in total, opening the investigation into the Long Island Serial Killer.¹⁶

Shannan’s remains were found in December 2011 in a marsh about eight miles from Gilgo Beach. Suffolk County police concluded she likely drowned in a drug-induced panic after fleeing her client’s home, but Mari refused to accept that. She became a vocal public advocate, pressed for a homicide investigation, and pursued civil litigation through John Ray. An independent autopsy Ray arranged, performed by forensic pathologist Michael Baden, found results “consistent with homicidal strangulation.” The official cause and manner of Shannan’s death remain listed as “undetermined.” Investigators have not connected Shannan’s death to Rex Heuermann, the Massapequa Park architect arrested in 2023 and later convicted of seven of the Gilgo Beach murders.¹⁷

Mari’s advocacy is the subject of Robert Kolker’s 2013 book Lost Girls and the 2020 Netflix film of the same name, in which Amy Ryan portrayed Mari and Oona Laurence played Sarra.¹⁸

1
ABC7 New York. Police: Shannan Gilbert’s Mom Stabbed; Daughter Found Covered in Blood
2
Record Online. Daughter Gets 25 to Life
3
NBC New York. Sarra Gilbert Arrest Trial Kill Mother
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CBS News. Long Island Serial Killer Shannan Gilbert Mother Slain Sister Sarra Gilbert Charged
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Record Online. Lawyer: Ellenville Murder Defendant Thought Mother Was Possessed
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People. Mari Gilbert Killed: Daughter Sarra Had Schizophrenia, Attorney Says
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PIX11. Shannan Gilbert’s Sister Heard Voices, Drowned a Puppy in Months Before Her Mother’s Murder
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NY Courts. People v. Gilbert
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Newsday. Sarra Gilbert Pleads Not Guilty in Mom Mari Gilbert’s Killing
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Times Union. Appeals Court Rejects Insanity Defense in Vicious Murder
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Daily Freeman. Defense Attorney Portrays Murder Suspect Sarra Gilbert
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FindLaw. People v. Gilbert
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Record Online. Gilbert Testifies Mom Deserved To Die
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Daily Freeman. Sarra Gilbert Sentenced to 25 Years to Life
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Daily Freeman. Sarra Gilbert Guilty of Murdering Mother in Ellenville Loses Appeal
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CBS News. Long Island Serial Killings Investigation Timeline
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CNN. Gilgo Beach Victims
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Netflix Tudum. Lost Girls: Release Date, News, True Story