A Princeton man was discovered dead in his New Jersey jail cell after killing his younger brother, eating his eyeball, and setting the household cat on fire.
According to the Mercer County Prosecutor’s Office, Matthew Hertgen, a former Wesleyan University soccer player whose terrible story shocked the country last year, was found unconscious inside Mercer County Jail on May 8.
Although the official cause of death has not yet been disclosed, the New York Post says that the death is being investigated as suicide.
Days after his arrest in February 2025, the 31-year-old attempted suicide once more while incarcerated by hanging himself in his cell.
In March, Mercer County Superior Court Judge Robert Lytle exonerated him of the murder of his brother Joseph Hertgen due to insanity.
Hertgen was charged with killing his 26-year-old brother severely during a psychotic episode, then disfiguring the body in what detectives called a “horrifying” scene.
“During his later years, Matthew struggled with severe and profound mental health issues; yet he expressed sorrow, remorse, and repentance in many ways,” his obituary said. Despite the brutality of the killing, Matthew’s family tried to remember him through the lens of his mental illness rather than just the violence that defined his final years.
On May 8, Matthew Hertgen, 31, who was charged with a horrific cannibalistic murder in Princeton, New Jersey, was discovered dead inside Mercer County Jail in what appeared to be a suicide.
In February 2025, Joseph Hertgen, 26, was discovered dead inside the brothers’ opulent Princeton apartment.
On February 22, 2025, police responded to a 911 call about a fire and a dead person in Princeton. They discovered Joseph laying in a pool of blood next to a knife.
The brothers’ opulent apartment close to the esteemed Ivy League university was the scene of the crime, according to the prosecution.
According to investigators, Matthew killed his younger brother by beating and stabbing him with a knife and golf clubs before ripping out and eating one of his eyeballs.
During the outburst, he was also charged by the authorities with killing the family cat and setting it on fire.
In addition to the graphic circumstances of the case, the Hertgens’ seemingly ideal upper-middle-class upbringing quickly attracted national attention.
The brothers grew up in a rich family in Toms River, New Jersey, under the leadership of IT executive David Hertgen, president and CFO of internet service provider WiLine Networks.
Later, the family moved to Princeton’s affluent Michelle Mews apartments, where monthly rent was reportedly between $6,000 and $7,000.
Family members recalled Joseph as being friendly and compassionate. He worked in finance after earning a degree in business administration from the University of Michigan.
Days after being arrested in February 2025 for killing his younger brother Joseph and then earning his eyeball, Hertgen had earlier tried to hang himself in jail.
Matthew, who was severely bearded, shared a terrifying selfie of himself lying still on the ground next to a cat toy the day before the horrific murder. Additionally, he was charged with lighting the cat on fire.
Matthew’s obituary stated, “He was such a kind person, had a great love of life and his smile brightened every room.” He developed an obsession with apocalyptic notions and persuaded himself that a “sacrificial murder could save” the planet.
Joseph’s passion for sports, ping pong, chess, and travel was highlighted in the memorial, but Matthew was not mentioned.
Prior to the murder, Matthew Hertgen was said to have suffered from serious mental illness and schizophrenia for years.
Hertgen suffered from complex delusions and thought he was seeing supernatural visions related to the end of the world, according to testimony given in court.
Dr. Gianni Pirelli, a forensic psychologist, stated in court that Hertgen occasionally thought he was Jesus Christ, God, the Anti-Christ, or possessed several souls. “Anytime he closes his eyes, he’s seeing tremendous visions,” Pirelli said.
According to the psychotherapist, Hertgen’s apocalyptic thoughts eventually led him to believe that a “sacrificial murder could save” the world.
Additionally, according to Pirelli’s testimony, Hertgen developed an obsession with concepts found in The Sacrificial Murder, a chapter of Swiss psychiatrist Carl Jung’s “Red Book.”
According to Pirelli’s testimony, “it kind of clicks for him and he puts two and two together.”
Joseph, his brother, earned a degree in business administration from the University of Michigan.
David Jr., the couple’s third sibling, is employed by their father’s business. On February 22, 2025, Joseph, 27, was beaten to death inside the family’s opulent Princeton condominium with a golf club and a knife. Joseph, left, David Jr., middle, and Matthew, right, are shown in the photo.
According to court documents, Hertgen’s mental health issues were long-standing; investigators and family members linked the start of his slide to his time spent in New York City in 2021.
Hertgen was almost wearing a green suicide-prevention vest during his initial court appearance following the killing. He was charged with murder and animal cruelty and appeared clearly stunned.
According to surveillance footage that was later displayed during the hearings, Joseph was seen trying to stop his bigger brother just before the deadly attack got out of control.
After specialists determined that Hertgen had severe schizophrenia at the time of the murder, Mercer County Superior Court Judge Robert Lytle found him not guilty by reason of insanity in March 2025.
Because of this ruling, Hertgen was spared a standard murder conviction and was instead sent to a mental health facility for an undetermined period of time.
