Blood-Coated Cup, Utensils Found Near Princeton Man's Body: Records

PRINCETON, NJ — The Princeton man who was charged in the death of his brother told a family member he experienced “terrifying visions” on the day of the murder, according to the police complaint.

The affidavit of probable cause has shed more light on the gruesome scene that awaited police officers when they visited the home of Matthew and Joseph Hertgen on Feb. 22 at Michelle Mews, Princeton.

Matthew Hertgen , 31, is charged with first-degree murder, along with various third and fourth-degree weapons offenses related to possession of a knife and a golf club in connection with the death of his brother Joseph Hertgen, 27.

Matthew Hertgen was with another family member until 10 p.m. that night, and a little more than an hour later, made the 911 call to report his brother's death, records show.

On that night, Princeton Police received a 911 call at 11:16 p.m. from Matthew Hertgen , who told them there was a fire and a body inside the house. Matthew Hertgen identified the body as that of his brother Joseph Hertgen and told dispatchers that Joseph had been dead on the floor for 30 to 40 minutes, the complaint said.

When dispatchers asked how Joseph Hertgen was injured, he said, “I’m not gonna go into any more details right now.” Matthew Hertgen also refused to answer further questions on whether any weapons were involved, according to the affidavit.

When officers arrived at the apartment, they found Joseph’s body on the floor by the dining table, with a pool of blood around his head and torso, the complaint said.

Joseph Hertgen appeared to have suffered severe blunt force trauma to the back of his head as well as a large laceration to his chest and abdomen which exposed his chest cavity. There were lacerations to his right eye and his right eyeball was not visible, the affidavit said.

Police found a cup of what they believed to be blood, along with blood-smeared utensils and a plate on the dining table next to Joseph Hertgen’s body. There was a golf club lying on the floor near the body, according to the complaint.

Officers also found a dead cat on an ottoman in the living room. The cat had suffered blunt force injuries and was also partially burned, the complaint said.

When officers detained Matthew Hertgen, they found abrasions and scratches on both his hands. When officers asked how and when Matthew Hertgen sustained the injuries, he told police he "went into a fit of madness, maybe like forty minutes ago."

Members of the Mercer County Homicide Task Force began their investigation and spoke to Matthew and Joseph’s brother, identified in the documents as “D.”

He told investigators that Matthew Hertgen suffered from severe mental illness for the past five years. On Feb. 22, Matthew was extremely "distressed, despondent, and experiencing terrifying visions," D told investigators.

Wanting to help him, the brother picked up Matthew around 4:30 p.m., went to a grocery store and then visited his house where they remained until 10 p.m..

D then drove Matthew Hertgen back home and walked him to the apartment. He also met Joseph Hertgen at the apartment and briefly had a conversation, before driving back to his own home.

Around 10:10 p.m. that night D sent Joseph Hertgen a text message telling him that Matthew Hertgen was struggling with “his visions” and to contact him if he needed help, the complaint said.

Around 10:28 p.m. D texted Matthew Hertgen inviting him to join him on a hike the next day and advised him to “hang in there.” Close to 45 minutes later, Matthew Hertgen called 911, telling police that Joseph was dead, the complaint said.

Joseph was born in Danbury, CT and graduated from Toms River North in 2016. He worked as an Analyst for Locust Point Capital in Red Bank, NJ since 2023.

“He was such a kind person, had a great love of life and his smile brightened every room,” according to his obituary.

Joseph’s funeral was held on March 1, at St. Luke Roman Catholic Church in Toms River.

Matthew Hertgen made his first virtual court appearance on Feb 27 during his pretrial detention hearing. He appeared before Judge Amber Gibbs, from a booth in Mercer County jail.

He will be back in court on Thursday for an in-person appearance.

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