The Princeton, New Jersey, man accused of killing his former college athlete brother and a cat, allegedly with a knife and golf club, posted eerie messages to social media months ago.

Matthew Hertgen, 31, is charged with first-degree murder in connection with the death of his 26-year-old brother, Joseph Hertgen. He is also charged with third- and fourth-degree weapons charges related to possession of a golf club and knife, as well as animal cruelty related to the death of a family cat.

“Who are you trying to strangle? And what god are you serving?” Hertgen wrote in one poem published to Facebook in September 2024. “I can see the knives sharpening. I can hear the arrows whizzing. I can feel my heart beating. But can he?”

The September poem becomes increasingly violent, describing a bloody strangulation.

Matthew Hertgen is charged with first-degree murder in connection with his brother Joseph Hertgen’s death. (Wesleyan.edu)

Joseph Hertgen was pronounced dead at the scene, and his autopsy results are pending. Local and state officials are investigating the 26-year-old’s death as a homicide.

Both brothers played college soccer — Matthew at Wesleyan University in Connecticut and Joseph at the University of Michigan.

An investigation into Joseph’s death is ongoing. Mercer County authorities are asking anyone with information about the alleged crime to contact the Homicide Task Force Sgt. Will Jett at 609-331-5010 or Det. Karl Johnson at 609-439-5258.