Authorities searched mountain trails and the Provo River on Friday looking for a Brigham Young University student near where two people took a bicycle that may belong to her.

A dam upstream at Deer Creek Reservoir was closed Thursday to lower the river and check for any sign of Camille Cleverley, missing for more than a week. Officers found no other evidence, Provo police Lt. John Guyerman said.

"We don't know if she's here. All we have to go on is a bicycle," he said.

Authorities believe Cleverley, who enjoyed riding her bike in the rugged areas around Provo, may have parked it and hiked one of the many trails leading into the Wasatch Mountains, Guyerman said.

The search along the river and the trials resumed Friday after being suspended overnight, police Capt. David Bolda said. Separately, more than 100 BYU students and staff signed up for a door-to-door canvass of city neighborhoods.

The bike was turned in by two people who admitted they had snatched it Saturday after finding it locked to a rack at Bridal Veil Falls along the Provo River, Guyerman said.

The search was concentrating in that mountainous area even as police worked to confirm that the bicycle was Cleverley's.

Cleverley, a 22-year-old senior from Boise, Idaho, was last seen Aug. 30. Her debit card was used the following day to buy doughnuts and energy drinks at a Provo store. Police have said the buyer was a young woman but they couldn't confirm if it was Cleverley.

Authorities have also questioned her boyfriend, David Sperry. He was cooperative and was given a "voice-stress analysis" test, said police Capt. Cliff Argyle, who is leading the investigation.

"They really worked him over," Sperry's father, Dick Sperry, told The Associated Press. "But that's their duty. They would do that with any boyfriend." He said his son "loves this girl" and would not have hurt her.

If Cleverley was abducted, brother David Cleverley publicly urged the perpetrator to release her — "if he has sensitivity and humanity."