‘A perfect, all-American family’: Former college athlete allegedly kills brother, eats eyeball in Princeton, NJ

Content warning: This article contains graphic descriptions of murder and mentions suicide. Please take care while reading.

A shocking and gruesome murder case has emerged from the otherwise bucolic university town, Princeton, NJ, where Matthew Hertgen is accused of brutally killing his brother, Joseph Hertgen, and then allegedly eating his eyeball in late February. Matthew is also accused of killing a cat in his brother’s apartment and setting the animal on fire.

According to the Mercer County Prosecutor, Princeton police were called to Joseph’s home on Feb. 22, this year, where they found Joseph, 26, dead from apparent blunt force trauma to the head and lacerations. A cat who lived in the apartment was also found dead, and multiple reports state the cat had been set on fire. Matthew, 31, was at his brother’s apartment, and it was later determined he called 911 to report the fire and a dead body. Matthew was arrested and charged with his brother’s murder and animal cruelty two days later.

Joseph and Matthew reportedly come from an affluent family in the Princeton area. Joseph was a successful former University of Michigan soccer player. Matthew played soccer at Wesleyan, according to MLive. As a boy, Joseph also played in the 2010 Little League World Series.

“It’s incredibly tragic,” a New Jersey police source told the New York Post of the case. “Matthew Hertgen came from what appeared to be a perfect, all-American family. No one could have predicted something like this would happen,” the source added.

A golf club, a blade, a missing eyeball, and a plate near the victim’s body

Matthew Hertgen’s poetry on Facebook… something was definitely going on with him before he allegedly killed his own brother, Joseph,(with a golf club and a knife???)- I need @NancyGrace’s take on this awful case! https://t.co/gG2nu7pTkr pic.twitter.com/2FS0hqSLsL

— Lauren Conlin (@conlin_lauren) February 26, 2025

Princeton police believe Matthew beat his brother with a golf club before stabbing and killing him with a blade. A source told the Post Joseph’s eyeball was also missing, and a plate was found next to his body suggesting Matthew may have eaten it. The cannibalism allegations are supported by a poem Matthew reportedly shared on Facebook months before the attack, seeming to describe a murder, with lines about sharpening knives and “blood oozing out of his eyes.” Matthew also shared a selfie on Facebook with a cat the day before his brother died. Matthew had no significant criminal record before his arrest.

According to the Post, Matthew wore a suicide vest at his first court appearance in late February after attempting suicide while in custody. Matthew was expected back in court on March 6. An official motive has not been reported so far. If convicted, Matthew could spend 30 years to life in prison.

It’s not immediately clear if Matthew and Joseph have any other siblings or if Matthew and Joseph’s parents had commented on the tragic situation. Joseph Mahon coached Joseph and Matthew’s soccer teams in high school.

“The Hertgens are good people,” Mahon told the Post. “His mom and dad are great. They treated me very well.” Mahon added, “It’s devastating. I just can’t wrap my head around it right now.”

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