Ex-star athlete accused in Princeton brother's grisly murder returns to court as prosecutors prep indictment

The Princeton, New Jersey, antheral known arsenic a prima pupil successful precocious school, who is present accused of sidesplitting his member and a household feline successful a "fit of madness" past month, is scheduled to look successful tribunal Monday afternoon.

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.

Monday's proceeding successful Mercer County Superior Court is simply a pre-indictment league – a procedural proceeding that apt won't past long, according to the court. 

Earlier this month, Hertgen consented to pretrial detention, meaning the prosecution didn't request to amusement grounds proving wherefore helium should beryllium held successful jailhouse earlier his trial.

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Matthew Hertgen appears successful a pre-trial detention proceeding astatine Mercer County Criminal Court connected Thursday, March 6, 2025, successful Trenton. Hertgen is accused of sidesplitting his younger member Joseph Hertgen successful February. (Stephanie Keith for Fox News Digital)

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 Fox News Digital reads.

When constabulary arrived to the grisley country that night, they recovered Matthew successful the residence on with his brother's body, which had important injuries to the caput – including a missing oculus  a–s good arsenic injuries to Joseph's thorax and precocious body. Police besides recovered a cupful of humor with "blood-smeared" utensils and a plate, the probable origin papers states.

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Joseph and Matthew Hertgen's precocious schoolhouse yearbook photos

Investigators further discovered a deceased feline connected an ottoman that appeared partially burned.

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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The Michelle Mews lodging analyzable successful Princeton, Feb. 26, 2025. Matthew Hertgen is alleged to person murdered his brother, Joseph, wrong their apartment. (Kevin Downs for Fox News Digital)

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 tribunal documents.

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Hertgen appeared successful tribunal connected March 6 for a detention hearing, which is typically erstwhile grounds is presented by the defence and prosecutors to find whether a suspect should beryllium held down bars oregon released, according to David Gelman, CEO of Gelman Law and a erstwhile authoritative successful New Jersey.

David Hertgen, left, Debra Hertgen and David Hertgen Jr. be the ceremonial for Joseph Hertgen astatine St. Luke Roman Catholic Church connected March 1, 2025 successful Toms River, New Jersey. (Stephanie Keith for Fox News Digital)

However, during that hearing, nary grounds was presented due to the fact that Hertgen consented to pretrial detention, meaning it was not indispensable for the prosecution to amusement grounds proving wherefore helium should beryllium held successful jailhouse earlier his trial.

None of Hertgen's household members were successful tribunal for that hearing. He is scheduled to instrumentality to tribunal connected March 24.

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

"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."

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Gelman, who is not progressive successful the case, besides said helium would petition a intelligence wellness valuation for the suspect.

Joseph Hertgen's elder photograph successful the 2016 Toms River North High School yearbook (Obtained by Fox News Digital)

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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Matthew Hertgen and his brothers, left. The 31-year-old, right, is accused of sidesplitting his younger brother, Joseph.

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.

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"If I was [the] 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.