The preppy Princeton, New Jersey man who allegedly killed his younger brother in the family’s upscale apartment also set the family cat on fire during the attack, a law enforcement source tells The Post.

A former college soccer player is accused of killing his younger brother and a cat, New Jersey prosecutors announced Monday, Feb. 24. The Mercer County Prosecutor’s Office said charges have been filed against Matthew Hertgen, 31, for first-degree murder and weapons offenses in connection with the death of his 26-year-old brother, Joseph Hertgen.

A former college soccer star has been charged with killing his younger brother and a pet cat inside a New Jersey apartment complex near the Princeton University campus, according to officials.

New Jersey authorities have arrested Princeton man Matthew Hertgen, who is accused of killing his brother, Joseph Hertgen, and a cat, allegedly with a knife and golf club.

A New Jersey man has been charged with first-degree murder in the death of his brother, who was a former University of Michigan soccer player.

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

Matthew Hertgen, who is a former Wesleyan student and soccer player, was charged with first-degree murder in the death of his brother, officials said.