Matthew Hartgen, the surviving brother of Princeton's murder suspect, sent a warning text to his youngest brother about an hour before he was killed.
Matthew Hertgen, 31 years old He was accused of murder His 26-year-old brother, Joseph Hartgen, is said to be a knife and a golf club at his family's Princeton apartment. He is also charged with animal cruelty related to the death of a cat.
Matthew's surviving brother allegedly spent time with him hours before the alleged crime on February 22, Saturday, according to a probable cause statement obtained by Fox News Digital.
The brothers clearly told police that Matthew had “suffered from severe mental illness for the past five years.”
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Matthew Hertgen has been accused of murdering his younger brother and cat in an apartment in Princeton, New Jersey. (University of Michigan/Mercer County Prosecutor/Google Maps)
“He further explained that when he spoke with Matthew earlier that day, he was extremely suffering, discouraged and experiencing a vision,” the document states. “I want to help him, [the surviving brother] I picked up Matthew on top [redacted] Around 4:30pm [The surviving brother] Matthew went to the grocery store and [the surviving brother’s] The residence… They stayed until around 10pm.”
The brothers then returned Matthew home, where they saw the victim, Joseph Hertgen. After a brief discussion, the surviving brother left and returned to his apartment.
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Matthew Hertgen appears at his pretrial detention hearing at Mercer County Criminal Court on March 6, 2025 in Trenton, New Jersey (Fox News Digital's Stephanie Keith)
Approximately an hour before the murder, the surviving brother told Joseph in the text that Matthew was struggling with “his vision” and contacted him if he needed help. Joseph replied, “I will.”
Approximately 45 minutes before Matthew called 911 and reported Joseph's body, his surviving brother texted him and invited him to go on a hike the next day.
“It's hanging there,” Matthew's brother texted him.
At about 11:16pm on February 22, police responded to a 911 call from Matthew reporting the fire and the body of his brother at the Michelle Muse Apartment Complex.
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Matthew Hertgen appears at his pretrial detention hearing at Mercer County Criminal Court on March 6, 2025 in Trenton, New Jersey (Fox News Digital's Stephanie Keith)
When the dispatcher asked Matthew how his brother was injured, he said, “I am not going to go into more details now,” a possible cause statement reads.
Possible Cause Statement: Read Mobile Users click here
Police arrive and discover that Matthew is in the residence with his brother's body. The brothers' bodies were seriously injured, including injuries to Joseph's chest and upper body, including lack of eyes. They also found a cup of blood with “bloody” tools and plates.
The Princeton man was accused of killing a former star athlete brother, a golf club cat and a knife near an Ivy League school
Photos from Joseph and Matthew Hartgen's High School Yearbook
Investigators also found a dead Ottoman cat that appeared to have been partially burned.
While interviewing Matthew, who was apparently cutting his hand, he reportedly told police “I've become fit for madness… maybe 40 minutes ago.”
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Matthew Hertgen has been accused of killing his younger brother and cat in his Princeton, New Jersey apartment. (Facebook)
According to David Germain Law's CEO and former New Jersey prosecutor David Germain said Hertgen appeared in court for a detention hearing Thursday morning.
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However, no evidence was presented during Thursday's hearing as Hartgen agreed to pretrial detention. This means that the prosecutors did not need to provide evidence to prove why they should be detained in prison before trial.
None of Hertgen's family was in court on Thursday. He is scheduled to return to court on March 24th.
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Family and friends gather for Joseph Hartgen's wake at Silverton Memorial Funeral Home on February 28, 2025 in Tom's River, New Jersey (Fox News Digital's Stephanie Keith)
The office of public defense attorneys representing Hertgen told Fox News Digital that the attorney had not commented on the pending case.
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Joseph Hertgen has been declared dead at the scene, and the results of his autopsy are pending. Local and state officials are investigating the death of the 26-year-old as a murder.
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Joseph and Matthew Hartgen were high school and college star soccer players. They were both athletes at Toms River High School, and Matthew continued his studies at Wesleyan University in Connecticut. Joseph Hertgen was hired to play football at the University of Michigan.
