A man trying to prevent his girlfriend from driving drunk after a party Saturday on Long Island was killed when he was dragged under her car while pleading with her to stop, according to Newsday.

Louis Wiederer, 26, was hanging onto Jesenia Vega's open driver's side window when she started her car and took off, dragging him until he lost his grip and fell under the car, the paper reports.

Click here to read Newsday's full report, including photos.

"You're going to get arrested," the paper reported a witness overhearing Wiederer tell Vega, 27. "You can't drive like that!'

But Vega told him, "Leave me alone!," and took off.

Suffolk police arrested her at the scene and charged her with driving while intoxicated. She pleaded not guilty Sunday and is currently being held in jail on $100,000 cash /$200,000 bond bail. Prosecutors vowed to upgrade the charges.

Wiederer was pronounced dead at the scene.

Wiederer, of Westbury, and Vega, of Carle Place, apparently were at an annual block party during the day. At roughly 9 p.m., Vega left, and that's when the arguing began.

"It looked like he was hitting her, but he was trying to stop her," neighbor Nick Montanino, 49, told Newsday. "She was totally irrational."

Vega then got into her car and drove off as her boyfriend clutched to the open driver's side window. She reportedly fishtailed down the block as her boyfriend's feet dragged. Soon after, Wiederer became lodged under the car — leaving what Newsday called "a trail of skid marks and blood."

Jay Steiner, a 60-year-old retired nurse, said the car sped through two stop signs before coming to a stop. He rushed to the vehicle but saw no signs of life.

He said he recalled Vega saying, "Oh, my God ... Don't tell me I just killed my fiance."

Newsday reported a woman who answered the door at Vega's house Sunday declined to comment. "We can't talk about it at this time," she reportedly told the paper.

However, Wiederer's mother commented.

"It's just a loss right now that's indescribable," Barbara Dempsey said.

Dempsey said she told her son to "Have a good time," and "I love you," before he left for the barbecue.

His response: "I love you, too."

Click here to read Newsday's full report, including photos.