The parents of a missing University of Vermont student made an impassioned plea for help in finding their daughter in a video posted on the Internet Tuesday, as the search intensified for her.

"I beg of everyone that hears this broadcast, if they know anything at all about where my daughter, Michelle, is today, or where she might have been Friday night, Saturday morning, they tell us instantly," John-Charles Quinn said in the video posted on the Burlington Police Department Web site.

Michelle Gardner-Quinn, 21, of Arlington, Va., disappeared Saturday as she walked from downtown to her campus dormitory. She has not been heard from since. She was reported missing Saturday when she failed to meet her parents, who were in town visiting for the weekend.

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"I think she's a fighter. I think she's resourceful," her mother, Diane, said in the video. "We pray that she's alive."

Federal agents and National Guard pilots met with local police, state police detectives and sex crimes investigators about the search.

"Over the past 24 hours we have received a number of helpful leads that have sent the investigation in a specific direction," police said, but did not elaborate.

Police previously said that one lead they were pursuing involved a man in a white, Subaru-style hatchback who reportedly tried to offer a woman a ride home around 20 minutes after Gardner-Quinn was last seen. Officials don't know whether that man was involved in the disappearance of the senior.

University of Vermont President Daniel Fogel said in a campus-wide e-mail that police and security patrols had been increased on campus and in dormitories and all "campus life safety systems" had been tested and found to be operating.

"As this very serious situation continues to unfold, I write to express both the University's distress about an apparent threat to one of our own, and our firm resolve to do all we can to assist the ongoing investigation, support the family, and keep our community fully informed," Fogel wrote.

About 150 people turned out for a candlelight vigil at the university Tuesday. One sign read, "I Am Scared," and another one read, "Somebody saw something. Spread the word. We want Michelle Back."

"It's sad," said friend Abby Carpenter, 20, of Greenwich, Conn., crying as she held a lighted white candle. "I wish they could find her."

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