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 Princeton man has been charged with killing his brother and a pet cat in an apartment Saturday night, authorities announced Monday. Matthew Hertgen, 31, is charged with first-degree murder and related weapon possession charges in the death of Joseph Hertgen, 26, the Mercer County Prosecutor’s Office said in a statement.

A former Wesleyan University soccer player is accused of murdering his younger brother, himself a former soccer player at the University of Michigan, in a violent attack near Princeton University over the weekend.

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

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.

The preppy Princeton, New Jersey man who allegedly murdered his younger brother and butchered the family feline inside their luxury apartment posed with an $8 cat toy the day before the gruesome killings.

The New Jersey man who allegedly beat and stabbed his younger brother to death in a ritzy Princeton apartment posted a creepy poem to social media that included a