Princeton preppy murder suspect had 'fit of madness,' 'terrifying visions' before killing brother: docs

The Princeton, New Jersey, antheral known arsenic a prima pupil successful precocious schoolhouse who is present accused of killing his brother and a household feline allegedly told constabulary helium had a "fit of madness" erstwhile they responded to the country of the crime, according to tribunal records obtained by section quality outlets.

Matthew Hertgen, 31, is accused of murdering his 26-year-old brother, Joseph Hertgen, successful the family's Princeton apartment, allegedly with a weapon and play club. He is besides charged with carnal cruelty related to the decease of a cat.

Princeton constabulary initially responded to a 911 telephone from Matthew connected Feb. 22 astir 11:16 p.m. reporting a occurrence and his brother's dormant assemblage astatine the Michelle Mews Apartments complex.

When a dispatcher asked Matthew however his member was injured, helium said, "I’m not gonna spell into immoderate much details close now," a probable origin connection obtained by NJ.com reads.

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Matthew Hertgen is accused of murdering his younger member and a feline successful their Princeton, New Jersey, apartment. (University of Michigan/ Mercer County prosecutor/ Google Maps)

Police arrived and recovered Matthew successful the residence on with his brother's body, which had important injuries to the caput — including a missing oculus — arsenic good arsenic injuries to Joseph's thorax and precocious body. Police besides recovered a cupful of humor with utensils and a plate, NJ.com reported, citing the probable origin document.

While interviewing Matthew, who seemingly had cuts connected his hands, helium told constabulary helium "went into a acceptable of madness … possibly similar forty minutes ago."

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Joseph and Matthew Hertgen's precocious schoolhouse yearbook photos.

Homicide detectives besides interviewed Matthew's different surviving brother, who told constabulary the 31-year-old fishy had struggled with intelligence wellness issues for astir 5 years. 

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The member had seen Matthew earlier successful the day, erstwhile helium had been experiencing a depressive occurrence and "terrifying visions," the member told police, according to NJ.com.

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Matthew Hertgen is accused of murdering his younger member and a feline successful their Princeton, New Jersey, apartment. (Facebook)

The gruesome details successful the probable origin connection volition apt beryllium discussed during Matthew's detention proceeding astatine 11 a.m. EST Thursday, according to David Gelman, CEO of Gelman Law and a erstwhile authoritative successful New Jersey.

"It's precise disturbing. You don't spot galore murders similar this," Gelman told Fox News Digital. "You tin spot it's precise personal. … I was a authoritative and I dealt with a ton of murders … and arsenic a defence attorney, I besides woody with murders. And erstwhile you spot these types of truly gruesome, graphic, heinous crimes. … I person a feeling that this idiosyncratic decidedly has immoderate benignant of intelligence illness."

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

(L-R) David Hertgen, Debra Hertgen and David Hertgen, Jr. be the ceremonial for Joseph Hertgen astatine St. Luke Roman Catholic Church connected Saturday, March 1, 2025 successful Toms River, NJ. Joesph was allegedly killed by his brother, Matthew, successful their Princeton flat connected Feb 22. (Stephanie Keith for Fox News Digital)

He described a detention proceeding arsenic "like a mini trial." New Jersey does not person bail, truthful the proceeding is to find whether Matthew is simply a big-enough menace to the nationalist that helium should stay down bars. The prosecution and the defence volition some bring definite grounds forward.

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"I was a defence attorney, I wouldn't combat it. I would say, you cognize what? We deliberation there's a intelligence issue," Gelman said.

The nationalist defender's office, which is representing Hertgen, told Fox News Digital that its attorneys bash not remark connected pending cases.

Matthew Hertgen appears successful tribunal for a detention proceeding connected Feb. 27. (Mercer County)

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Joseph Hertgen was pronounced dormant astatine the scene, and his autopsy results are pending. Local and authorities officials are investigating the 26-year-old's decease arsenic a homicide.

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Joseph and Matthew Hertgen were prima shot players successful precocious schoolhouse and college. They were some athletes astatine Toms River High School, and Matthew went connected to survey astatine Wesleyan University successful Connecticut. Joseph Hertgen was recruited to play shot astatine the University of Michigan.