Matthew Hertgen, the cannibal who butchered his younger brother and consumed his eyeball, has been found dead in his jail cell months after a judge ruled he was not guilty by reason of insanity.
Death in custody
Hertgen, 31, was discovered unresponsive inside the Mercer County Correction Center in Hopewell Township, New Jersey, on May 8, according to the Mercer County Prosecutor’s Office. Officials have not yet released a formal cause of death, but the death is being treated as a suicide. The former university soccer player had attempted to take his own life by hanging just days after his arrest in February 2025.
His obituary said he “struggled with severe and profound mental health issues” in his later years, adding that he “expressed sorrow, remorse, and repentance in many ways.” It continued: “He departed with the love, friendship and forgiveness of his family and the eternal hope of salvation.”
The attack on Joseph
The killing unfolded on February 22, 2025, inside the brothers’ luxury apartment at the Michelle Mews Apartments in Princeton, close to the Ivy League university. Officers responded to reports of a fire and a dead body and found Joseph Hertgen, 27, lying in a pool of blood beside a knife.
Investigators described how Matthew used a knife and golf clubs to beat and stab his younger brother to death before tearing out one of his eyes and eating it. He was also accused of killing the family cat by beating, stabbing and setting the animal on fire. Surveillance footage shown during proceedings reportedly captured Joseph trying to restrain his older brother moments before the attack.
Matthew Hertgen made the 911 call himself, telling dispatchers his brother had been dead for more than 30 minutes. Joseph, who graduated from the University of Michigan’s business school and worked as an analyst in Red Bank, was remembered in his obituary as a “kind person” with a “great love of life” and a smile that “brightened every room.”
The insanity defence and its consequences
On March 19, 2026, Mercer County Superior Court Judge Robert Lytle ruled Matthew Hertgen not guilty by reason of insanity after experts concluded he was suffering from severe schizophrenia during the killing. Prosecutors conceded that Hertgen met the criteria for the defence.
The ruling meant Hertgen avoided a traditional murder conviction and instead faced indefinite confinement in a secure psychiatric institution. Sentencing had been scheduled for May 1, 2026—just a week before his death. Forensic psychologist Dr Gianni Pirelli testified that Hertgen had been struggling with severe mental illness since 2021, experiencing constant psychosis and hallucinations with religious and apocalyptic overtones. Hertgen believed at different times he was Jesus Christ, God, the Anti-Christ, or possessed multiple souls. He convinced himself that a “sacrificial murder could save” the world and that an evil spirit had overtaken him, rendering him beyond the help of medication.
Judge Lytle stated that in Hertgen’s delusional state, the act was “not wrong in the ordinary moral sense. It was required.” He concluded that Hertgen was labouring under a defect of reason from disease of the mind. The brothers grew up in a wealthy family in New Jersey, and the gruesome nature of the crime shocked the US, in particular because of their picture-perfect upbringing. Matthew played soccer at Wesleyan University, graduating in 2015, while Joseph was a three-time Academic All-Big Ten soccer player at the University of Michigan.
