A preppy jerk illegally killed a hungry fox at a Long Island park — and now cops are on the hunt for him.

The red fox had been approaching cars in Field 2 of Robert Moses State Park last Saturday when it was shot in the neck by a crossbow-wielding, Jaguar-driving man wearing a black suit jacket, button-down pink shirt and jeans, witness Christine Daly told The Post.

“Letting a fox walk up to you and just shooting it is — I don’t even have a word for that, I don’t know,” Daly said. “It just seemed so wrong that someone would do this. It’s cowardly. He’s too much of a coward go on real hunt in the woods and try this.”

Daly, 31, of Glen Oaks, Queens, was in the picturesque Suffolk County park just before 4:30 p.m. to take photos of wildlife, including snowy owls, hawks and white-tailed deer.

After spotting the little vulpine chilling out in the snow, Daly parked her car and grabbed her camera.

But it was already too late.

The man –dressed like someone out of a J. Crew catalogue– was already putting his crossbow into the trunk of his white Jaguar X-type when she approached.

“He saw me coming and I jogged up a little bit closer, I said something like, ‘I’m taking pictures of the foxes,’ And he said, ‘Two of them just ran that way,’ and pointed back to the direction I came from,” she recalled.

That’s when Daly noticed the dead fox.

The man then told her, “One of them was limping. It looks like it might have been injured” — and then sped off in his fancy car.

“I knew something was wrong,” said Daly.

The man circled the area in his car once before taking off for good. Daly managed to snap pictures of the man’s license plate and turned the snaps over to park police.

“It just felt so wrong that somebody would come to the beach with a weapon in the trunk, ready to go to shoot a little fox that was coming up to every car looking for food,” said Daly, who put photos and a description of the ordeal on Facebook, where it shared more than 1,800 times.

The dead fox, which had a No. 14 tag on its ear, was removed up by police.

Crossbow hunting, while permitted in parts of New York State during certain seasons, is against the law on Long Island and Westchester County.

“State Park Police are actively investigating the incident and urge the public to continue offering assistance if they have any information that may be relevant to the case,” a parks spokesman said.