Man Who Killed His Brother and Ate His Eyeball Found Dead in New Jersey Jail
Matthew Hertgen, the New Jersey man who was found not guilty by reason of insanity for killing his younger brother and consuming his eyeball, has died in jail. He was 32.
Hertgen was found dead at Mercer County Jail on May 8 in what authorities described as an apparent suicide. His cause of death remains pending an autopsy, the Mercer County Prosecutor's Office confirmed to NJ.com. It was not the first time — a week after his February 2025 arrest, Hertgen attempted to hang himself in his cell at the same facility.
The Crime
On the night of Feb. 22, 2025, Hertgen called 911 himself to report that his brother Joseph, 26, was dead on the floor of their Princeton, New Jersey apartment. Officers arrived to find Joseph had been beaten and stabbed to death with a golf club and a knife. His right eyeball was missing. A bloody plate, fork, and knife were found near the body, leading investigators to conclude Hertgen had consumed it. The family cat had also been set on fire.
Months before the killing, Hertgen had posted a series of poems on Facebook that included lines about knives sharpening and blood oozing from eyes. The night of the murder, the brothers' older sibling David had texted Joseph to warn him that Matthew was in distress and experiencing "visions" — telling Joseph to reach out if he needed help. Joseph responded, "Will do." He never sent another message.
The Legal Outcome
In March 2026, Mercer County Superior Court Judge Robert Lytle found Hertgen not criminally responsible for his brother's death by reason of insanity — a conclusion that both prosecution and defense experts agreed on. Forensic psychologist Dr. Gianni Pirelli testified that Hertgen had been diagnosed with schizophrenia and had experienced severe psychosis at the time of the killing. He believed himself at various times to be Jesus Christ, the anti-Christ, God, or a figure with multiple souls. He also believed the world was on the brink of the apocalypse and that a "sacrificial murder could save it," Pirelli testified.
David Hertgen, the brothers' older sibling, had previously told investigators that Matthew had been experiencing severe mental illness for five years and was "extremely distressed, despondent and experiencing terrifying visions" on the day of Joseph's death.
The Family's Response
Following confirmation of Hertgen's death, his family issued a statement encouraging donations to a mental health nonprofit in his memory. The family did not comment further publicly.
Hertgen was a former varsity soccer player at Wesleyan University. Joseph, his younger brother, had been a standout high school soccer player who went on to graduate from the University of Michigan. The brothers had grown up in a home in Toms River, New Jersey before the family relocated to Princeton.
The case drew significant national attention both for the nature of the crime and for what it illustrated about the failures in identifying and treating severe mental illness before tragedy occurs.
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