Savage timeline in Princeton preppy murder could bolster insanity defense for suspect brother: expert

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NJ man accused of killing his brother, family cat in ‘gruesome’ case: ‘Sick and sadistic’

Criminal defense attorney Jonna Spilbor joined ‘America’s Newsroom’ to discuss her take on the allegations against 31-year-old Matthew Hertgen, who allegedly brutally murdered his brother and their family cat.

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The Princeton, New Jersey, man known as a star student in high school who is now accused of killing his brother and a family cat likely had a mental health breakdown that ultimately destroyed his family, according to a legal expert.

Matthew Hertgen, 31, is accused of murdering his 26-year-old brother, Joseph Hertgen, in the family’s Princeton apartment, allegedly with a knife and golf club. He is also charged with animal cruelty related to the death of a cat.

One of Matthew Hertgen’s friends from Toms River High School told Fox News Digital that he has “nothing bad to say” about the former soccer player, who went on to study at Wesleyan University in Connecticut. Joseph Hertgen also played soccer at Toms River before he was recruited to the University of Michigan.

“He was just a cool kid who played soccer, got good grades, funny,” the friend said, adding that “Matt was a cool guy” and the recent news “just doesn’t sound like him.”

PRINCETON PREPPY ACCUSED IN BROTHER’S GRUESOME MURDER HEADS TO COURT: WHAT TO KNOW

Matthew Hertgen’s senior photo in the 2011 Toms River North High School yearbook. (Obtained by Fox News Digital)

Matthew Hertgen appears in court for a detention hearing on Feb. 27. (Mercer County)

But that was about 14 years ago, when both Matthew and Joseph had their whole lives ahead of them. One high school yearbook page shows that Matthew Hertgen, along with another female classmate, were voted “Best All Around.”

A photo from the 2011 Toms River North High School yearbook shows Matthew Hertgen with a schoolmate where they were both named “Best All Around.” (Obtained by Fox News Digital)

More recently, Joseph was working as an analyst at Locust Point Capital in Red Bank at the time of his death. Matthew’s professional career remains unclear. 

In May and September of last year, Matthew shared some disturbing graphic poetry as well as strange abstract artwork on his Facebook profile.

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Joseph Hertgen’s senior photo in the 2016 Toms River North High School yearbook. (Obtained by Fox News Digital)

“These are brilliant individuals. The intellectual ability is there,” attorney Daniel Gotlin of Gotlin & Jaffe in New York told Fox News Digital of the Hertgen brothers, but he added that Matthew “obviously” had some “mental health issues.”

Gotlin, who is not involved in the Hertgen case, successfully tried a mental health defense in 2014 while representing a man accused of fatally stabbing his mother. He believes Matthew’s public defenders will consider an insanity plea for the 31-year-old suspect, which would ensure that he is kept in the custody of a mental health facility rather than prison until and if he is determined not to be a threat to society.

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General view of the Michelle Mews housing complex in Princeton, N.J., on Feb. 26, 2025. Matthew Hertgen is alleged to have murdered his brother, Joseph, inside their apartment. (Kevin Downs for Fox News Digital)

“There’s absolutely no doubt he’s got a phychiatric disorder,” he said. “I don’t know what kind of physical evidence they have on him, but if [prosecutors] have got a good case, you’ve got to look at a psychiatric defense.”

Gotlin believes it is “very unlikely this guy would see the light of day” if he were to be committed to a mental health facility.

PRINCETON MAN ACCUSED OF KILLING FORMER STAR ATHLETE BROTHER, CAT WITH GOLF CLUB, KNIFE NEAR IVY LEAGUE SCHOOL

Joseph “Joey” Hertgen signs with the University of Michigan as a soccer player. (Toms River Regional School District)

The defense attorney noted the possibility of schizophrenia, which typically appears in men when they are in their late teens and early 20s through their late 20s.

Hertgen appeared virtually for a remote pretrial detention hearing in Mercer County on Thursday morning. His family was not in attendance.

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A photo from the 2011 Toms River North High School yearbook shows Matthew Hertgen playing soccer for the school team. (Obtained by Fox News Digital)

Assistant deputy public defender Jason Matey, assistant prosecutor Tim McCann and Judge Amber Gibbs ultimately decided to reschedule for March 6 to allow both prosecutors and the defense more time to gather discovery, or information about Hertgen’s case.

Princeton police initially responded to a 911 call on Feb. 22 around 11:16 p.m. reporting a fire and a dead body at the Michelle Mews Apartments complex.

Upon arrival, police found Matthew Hertgen, who was determined to be the 911 caller, in the residence along with his brother’s body, which “exhibited signs of blunt force trauma and lacerations,” the Mercer County Prosecutor’s Office said in a press release.

A photo from the 2011 Toms River North High School yearbook shows Matthew Hertgen with classmates where they said the thing they’d miss most about school was playing fiddlestick lacrosse in gym class. (Obtained by Fox News Digital)

Police believe Matthew may have ripped out his brother’s eye and tried to eat it, a law enforcement source told the New York Post.

Authorities have yet to describe any kind of motive related to Hertgen’s murder charges.

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Princeton police initially responded to a 911 call on Feb. 22 at around 11:16 p.m. reporting a fire and a dead body at the Michelle Mews Apartments complex. (University of Michigan | Wesleyan University | Google Maps)

Gotlin said that while it’s uncommon for people from affluent families to descend into a mental health crisis that ends in death, it is not unheard of. He mentioned the case of Luigi Mangione, the suspect accused of killing UnitedHealthcare CEO Brian Thompson in December on a sidewalk in Manhattan.

Mangione graduated valedictorian from the Gilman School, a private all-boys high school in Baltimore, in 2016. He went on to receive his bachelor’s and master’s degrees in computer science from the University of Pennsylvania in 2020.

An empty courthouse is seen as lawyers convene and Judge Gibbs presides over the Matthew Hertgen murder hearing by video conference at the Mercer County Criminal Court on Feb. 27, 2025, in Trenton, N.J. (Stephanie Keith for Fox News Digital)

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“It’s not common, but the best example of it is Luigi Mangione. He grew up, went to the best schools, private schools … and he’s obviously mentally ill,” Gotlin said. “There’s no question about it. People get sick. Mental illness is something, unfortunately, the medical industry hasn’t really conquered.”

Joseph Hertgen was pronounced dead at the scene, and his autopsy results are pending. Local and state officials are investigating the 26-year-old’s death as a homicide.

An investigation into Joseph’s death is ongoing. 

Audrey Conklin is a digital reporter for Fox News Digital and FOX Business. Email tips to audrey.conklin@fox.com or on Twitter at @audpants.