Preppy Princeton killer who slayed brother and ate his eyeball found dead in jail cell

A Princeton man who killed his brother and ate his eye has died in jail.

Matthew Hertgen, 31, was found dead in his cell months after a judge ruled he was not responsible for his brother's death due to severe mental illness.

It is hard to imagine the pain a family feels when a loved one turns into a stranger. This story is a tragic look at how quickly a life can fall apart when the mind breaks.

What Happened

Matthew Hertgen was found dead in his Mercer County Jail cell on May 8. Officials have not yet confirmed the cause of death, but it is being treated as a suicide.

Hertgen had been in custody since February 2025. He was arrested after killing his 26-year-old brother, Joseph, in their apartment. The crime was violent and included acts of cannibalism.

In March 2025, a judge ruled that Hertgen was not guilty by reason of insanity. Experts testified that he suffered from schizophrenia and believed he was on a divine mission to save the world.

What the evidence shows

• Matthew Hertgen was 31 years old at the time of his death.
• He was found not guilty by reason of insanity on March 19, 2025.
• The crime involved the use of golf clubs and a knife.
• Forensic experts diagnosed him with schizophrenia and delusions.
• Hertgen had previously attempted to hang himself in jail one week after his initial arrest.

The Bigger Question

We often look at these cases and ask how someone could do something so horrific. But we should also ask how the system handles those who are clearly suffering from a total break with reality.

If someone is found not guilty because they are too sick to understand their actions, where is the line between punishment and medical care? We have to wonder if the system is equipped to help people like Hertgen before they reach a point of no return.

The Other Side

His family described him as a caring person who struggled with profound mental health issues for years. They noted that he expressed deep remorse for his actions before his death. This argument carries weight given the medical testimony regarding his severe schizophrenia.

What Happens Now

This death closes the legal chapter on a case that shocked the community. For the family, it is another layer of grief in a situation that was already devastating.

It also raises questions about how jails manage inmates who are known to be a danger to themselves. The facility will likely face scrutiny over how they monitored a man who had already tried to take his own life.

What We Still Don't Know

1. What was the official cause of death determined by the medical examiner?
2. What specific safety protocols were in place for Hertgen at the time of his death?
3. How did the jail staff respond to his previous suicide attempt in February?