Insanity verdict in brother’s killing

Onetime Toms River soccer standout is committed

Kathleen Hopkins

Asbury Park Press | USA TODAY NETWORK – NEW JERSEY

TRENTON – A former Toms River North soccer star who stabbed and beat his younger brother to death and also killed his cat has been found not guilty of murder, animal cruelty and related weapons charges by a judge who said the defendant believed he was fending off a “spiritual catastrophe” by committing the acts.

Superior Court Judge Robert Lytle found Matthew Hertgen, 32, of Princeton, not guilty by reason of insanity of murder, animal cruelty and weapons offenses related to the events of Feb. 22, 2025.

Matthew Hertgen enters Superior Court Judge Sherry Wilson’s courtroom in Mercer County State Superior Court for his detention hearing on March 6, 2025. He was accused of killing his brother in Princeton.

THOMAS P. COSTELLO / ASBURY PARK PRESS

Lytle rendered the verdict at a bench trial March 18 at which the only witness, a psychologist, testified that Hertgen was so mentally ill at the time he killed his brother, Joseph, 27, and the family’s cat in their Princeton home that he did not understand the nature of his actions or that they were wrong.

The psychologist, Gianni Pirelli, testified Matthew Hertgen had been mentally ill since at least 2021 and suffered from severe schizophrenia in the time leading up to and including the killings. Pirelli, called to testify by defense attorney Mitchell Ansell, said the mental illness was marked by hallucinations and religious delusions that at times included demons, witches and a belief that he possessed two souls.

At the time of the killings, Hertgen “believed that he was Jesus and there was going to be an apocalypse,” Pirelli testified.

In rendering his verdict, Lytle said the defendant “believed and continues to believe that he possesses two souls, that those souls were turning dark and that he was somehow connected to both Christ and the anti-Christ.

“He believed if he did not act, spiritual catastrophe would follow,” the judge said.

The defendant believed he had to “commit an act of evil in order to save his soul,” Lytle said.

Matthew Hertgen killed his younger brother in their Princeton home after another brother, David, dropped him off on the night of Feb. 22, 2025, according to the judge’s narrative of events and police reports.

David Hertgen texted Joseph after dropping off Matthew to tell the younger brother that Matthew was “struggling with visions,” and to contact him if he needed help.

After that, Matthew Hertgen was captured on surveillance video engaged in a violent struggle with Joseph in which he repeatedly struck his younger brother and tackled him to the floor before closing the window blinds at 10:28 p.m., cutting off the view of the surveillance camera, the judge said.

At 11:16 p.m, Matthew Hertgen called 911 to report a fire and “a dead body” at the house, Lytle said.

He told the dispatcher the deceased was his brother, Joseph, who had been dead for 30 to 40 minutes, the judge said.

When the dispatcher asked the defendant how Joseph was injured, he responded, “I’m not going into any more details right now,” Lytle said.

Responding officers found Joseph lifeless on the floor of the home and the family cat on an ottoman in the living room, stabbed to death and partially burned, the judge said.

Joseph Hertgen suffered severe blunt force trauma to the back of his head and lacerations to his chest and abdomen, the judge said. A bloody golf club was found nearby his body, Lytle said.

When officers questioned Matthew Hertgen about abrasions and scratches on both his hands, he told them he “went into a fit of madness, maybe 40 minutes ago,” the judge said.

Officers also collected a bloody knife from Joseph’s chest and another knife with blood stains and fur on it from the ottoman, near the dead cat, the judge said.

The state did not contest Pirelli’s conclusions, as an evaluation by the state’s expert agreed that Matthew Hertgen was legally insane when he committed the killings.

Lytle ordered the defendant be committed to the custody of the state health commissioner for further evaluation. He said he would review a report of that evaluation on May 1 to consider whether Hertgen would remain hospitalized.

Both Matthew and Joseph Hertgen played soccer at Toms River High School North.

In 2015, Joseph Hertgen was named by the Asbury Park Press to its All-Shore Second Team.

Matthew was a 2010 Asbury Park Press honoree.

He continued to play soccer at Wesleyan University, while Joseph played soccer for the University of Michigan.

Kathleen Hopkins covers crime, court cases and legal issues. Contact her at khopkins@app.com.