Preppy Princeton murder suspect Matthew Hertgen posed in creepy pic with cat toy 1 day before allegedly killing brother, cat

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.

In the creepy pic, Matthew Hertgen, 31, displayed the same thousand-yard stare he had in his mugshot the following day — after cops arrested him for beating and slashing his brother, Joseph Hertgen, to death Saturday night.

Hertgen also posted eerie poems to Facebook during the months before the killing — one of which included verses about “knives sharpening” and “blood oozing out of his eyes.”

Police say Hertgen used a knife and a golf club to kill both his brother and the cat at about 11:15 p.m. Saturday night in Princeton.

Authorities have charged him with murder, and he faces life in prison if convicted.