A disturbing case out of Princeton has taken another tragic turn after 32-year-old Matthew Hertgen was found dead inside his jail cell earlier this month. According to reports, Hertgen died on May 8 while being held at the Mercer County Jail. Jail officials said his death is being investigated as an apparent suicide, though the official cause of death remains pending autopsy results.
Hertgen had been at the center of a horrifying homicide case that shocked residents across New Jersey earlier in 2025. Prosecutors accused him of brutally killing his 26-year-old younger brother, Joseph Hertgen, inside the family’s apartment in Princeton in February. Investigators alleged that the attack involved extreme violence, with authorities claiming Matthew used a knife and golf clubs during the deadly assault.
Court documents and media reports revealed disturbing allegations surrounding the crime scene. Prosecutors said Matthew Hertgen allegedly mutilated his brother’s body after the killing, including claims that he removed and consumed one of Joseph’s eyeballs. Authorities also alleged that the family’s cat was killed and set on fire during the incident, adding to the gruesome nature of the case.
As the case moved through court proceedings, mental health became a major focus of the investigation. In March 2025, a judge ruled Matthew Hertgen not guilty by reason of insanity after psychiatric experts testified that he had been suffering from severe psychosis linked to schizophrenia. According to testimony presented in court, Hertgen experienced escalating delusions involving religious, supernatural, and apocalyptic visions in the weeks leading up to the killing.
Doctors involved in the case reportedly told the court that Hertgen believed he was receiving prophetic messages and divine visions. Medical experts concluded that his mental state had deteriorated significantly before the attack and that he was legally insane at the time of the killing. Following the ruling, the court had planned a hearing to determine his long-term placement, which was expected to involve confinement within New Jersey’s psychiatric hospital system rather than a traditional prison sentence.
Reports also indicated that Hertgen had previously attempted suicide while in custody shortly after his arrest. Mental health professionals reportedly warned that he continued experiencing severe psychotic episodes and hallucinations during his incarceration.
Following his death, an online obituary released by his family described the profound impact mental illness had on his life. Loved ones remembered Matthew as a caring and intelligent individual who once excelled academically and athletically. According to the obituary, he attended Wesleyan University, where he played soccer and earned a degree in microbiology and biochemistry before later working in a senior finance role at a telecommunications company.
The obituary also acknowledged his long struggle with severe mental illness in recent years. Family members wrote that despite the horrifying circumstances surrounding the case, Matthew expressed sorrow, remorse, and repentance before his death. They added that he died surrounded by the forgiveness and love of his family, who continued to hope for peace amid an unimaginable tragedy.
