Matthew Hertgen, 32, was found not guilty by reason of insanity in the killing of his brother Joseph Hertgen, 27, during a bench trial before Mercer County Superior Court Judge Robert Lytle on Wednesday. The judge agreed with mental health experts from both sides that Hertgen was legally insane at the time of the killing on February 22, 2025. Prosecutors conceded they could not contest the insanity defense.
Dr. Gianni Pirelli, a clinical and forensic psychologist, testified that Hertgen is schizophrenic and has struggled with severe mental illness since 2021. Hergen told a psychologist he believes “the spirit that overtook him in 2021 is basically too powerful for any medications or mental health treatment.” Pirelli testified, “Anytime he closes his eyes, he’s seeing tremendous visions.” At the time of the killing, Hertgen was operating under apocalyptic religious delusions, believing he was Jesus and that an apocalypse was coming.
On February 22, Hertgen spent the evening with another brother who texted Joseph at 10:10 p.m. warning that Matthew was struggling with “his visions.” Less than an hour later, at 11:16 p.m., Hertgen called 911 reporting a fire and a body. Officers found Joseph Hertgen on the floor surrounded by a large pool of blood with severe blunt force trauma to the back of his head, a large laceration to his chest and abdomen, and lacerations to his right eye. A golf club lay on the floor near the body. Officers also found the family’s cat dead on an ottoman—beaten, stabbed and set on fire. According to court records, Joseph was a University of Michigan soccer graduate and had been working as an analyst at Locust Point Capital since December 2023.
Because of the not guilty by reason of insanity verdict, Hertgen will remain in custody until sentencing May 1, at which point he is expected to be committed to a psychiatric facility.
This article is an AI-assisted summary. All facts and figures are drawn from the original report: https://patch.com/new-jersey/tomsriver/brother-found-not-guilty-reason-insanity-killing-toms-river-grad