Princeton Preppy Murder Suspect Had 'Fit of Madness,' 'Terrifying Visions' Before Killing Brother

A once-promising Princeton man, Matthew Hertgen, now stands accused of a grisly crime that has left his family and community reeling. Court documents reveal that the 31-year-old allegedly admitted to police that he experienced a "fit of madness" before brutally killing his 26-year-old brother, Joseph Hertgen, and the family cat.

Police were called to the Michelle Mews Apartments in Princeton late on February 22 after Matthew dialed 911, reporting both a fire and his brother's death. When pressed for details by the dispatcher, Matthew cryptically replied, "I’m not gonna go into any more details right now," as noted in the probable cause statement. Upon arrival, officers found Joseph's body bearing severe injuries, including a missing eye and multiple wounds to his chest and upper body. The scene also contained unsettling evidence: a cup of blood alongside utensils and a plate.

Matthew, who had visible cuts on his hands, reportedly told investigators, "I went into a fit of madness… maybe like forty minutes ago." According to his surviving brother, Matthew had been battling mental health issues for the past five years and had described experiencing "terrifying visions" earlier that day.

The crime has drawn comparisons to the most disturbing cases of domestic violence. "It's very disturbing. You don't see many murders like this," said David Gelman, a former prosecutor and current defense attorney. He suggested that Matthew’s defense team might focus on his mental health, adding that such gruesome, personal crimes often indicate deeper psychological issues.

New Jersey's legal approach to detention hearings—where bail is not an option—means the court will assess whether Matthew poses a significant public threat. The hearing, described as a "mini trial," will see both sides present evidence to determine if he should remain behind bars.

Joseph Hertgen, a former soccer standout at the University of Michigan, shared an athletic legacy with his older brother, who had played at Wesleyan University. The two were star players during their high school days at Toms River High School, making the tragic turn of events even harder to fathom for those who knew them.

Matthew's public defender has declined to comment on the case, and autopsy results for Joseph are still pending. Meanwhile, the investigation continues as local and state authorities piece together the events leading to this horrifying crime.