A 20-year-old Pennsylvania dance student who vanished last week while on Thanksgiving break in her hometown was killed by her on-again, off-again boyfriend, who then dumped her body in a park "like garbage," a prosecutor said Saturday.

Onondaga County District Attorney William Fitzpatrick said 21-year-old Steven Pieper of Liverpool, N.Y., was charged with murder in the death of Jenni-Lyn Watson, a junior dance major at Mercyhurst College in Erie, Pa. He pleaded not guilty Saturday night at his initial appearance in Clay town court.

Pieper was held without bail because of the seriousness of the charge, Fitzpatrick told the Syracuse Post-Standard.

Pieper did not have a phone number listed at his home address. A message left at a relative's house was not immediately returned Saturday. It was unclear whether he had an attorney.

Eden Mishler, a dance major who met Watson three years ago during her freshman year at Mercyhurst College, told The Associated Press that she had met Pieper several times but didn't know him that well.

"She would talk to us, just saying, after they broke up, that he was trying to contact her and friend request her on Facebook," the 21-year-old Mishler said. "She was avoiding him."

But she said the two had a rocky relationship, and there was some jealousy. Nevertheless, Mishler thought he cared for her.

On her Facebook page, Mishler posted: "Rest in peace Jenni-Lyn Watson. You are truly loved and will be missed so much. I love you ballet buddy!"

The arrest came hours after searchers combing through woods for any sign of Watson found the body of a woman believed to be the missing student covered in debris behind a storage shed in a swampy area of Clay Central Park, Fitzpatrick said.

The site was part of a 1,200-acre area canvassed by more than 100 police and volunteers in suburban Syracuse.

Fitzpatrick said Pieper was upset when Watson tried to end their relationship in early October. He said investigators believe Pieper killed Watson at her parents' house on Nov. 19, and her body was "dumped, frankly, like garbage," in the park.

"We do not believe she left that house alive," Fitzpatrick said.

Fitzpatrick said the remains have not been positively identified but were consistent in age and race with Watson. Her parents have been notified. An autopsy was expected to be performed Sunday to determine the cause of death, he said.

Watson went missing last Friday, a day after arriving at her family's home north of Syracuse.

The search effort was stepped up Friday. Undersheriff Warren Darby said they doubled the area where they were looking, and volunteers copied and handed out thousands of fliers and held vigils.

The body was found in the search, about two miles north of Watson's home. Investigators were led to the wooded area near her home after a cell phone transmission the day she disappeared.