Police in Provo, Utah, were trying to track down the person who used the ATM card of a missing Brigham Young University senior to buy donuts and juice at a local convenience store, FOX News has learned.

But they've hit a snag: The Provo shop's security camera wasn't working when the cashier swiped the card on the purchase at about 11 a.m. Friday, a day after 22-year-old Camille Cleverley was reported missing.

Authorities told FOX on Wednesday that they've interviewed the person working the register that morning, but haven't yet determined who made the purchase. There's still the possibility that Cleverley herself was the one who used her own debit card. The store is close to her off-campus apartment.

Cleverley's boyfriend said Camille might have bought juice, but the donuts didn't sound like something she'd pick up.

Dave Sperry told FOX he last saw his girlfriend Wednesday evening and nothing seemed amiss.

"Everything was good. She was happy, smiling," he said. "Everything seemed to be going well."

The Boise, Idaho, native — who was going into her senior year at Brigham Young in Provo and also worked at the university — disappeared on Thursday with her mountain bike. No one has heard from her since.

So far, there is no person of interest in the case, police told FOX. More than 20 people who know Cleverley have been interviewed, said Provo Police Capt. Cliff Argyle.

Cleverley was reported missing on Thursday by her roommates, according to investigators, and was last seen in the Provo area, where her campus is located.

A man named Jonathan Allred came forward to report a sighting of Cleverley Thursday afternoon, riding her bike between 5 and 6 p.m. near the BYU library, according to The Salt Lake City Tribune.

If it was in fact Cleverley Allred saw, that could have been the last known sighting of the student before she vanished. Her roommate saw her at noon that same day.

Her family has said her white and lime-green striped sneakers are missing from her closet, as are her green basketball shorts, according to the newspaper.

Meanwhile, searchers embarked on another hunt in the region Wednesday for clues in the case. They started at Canyon View Park to look at the areas bordering the bike trails Cleverley was known to ride on.

The terrain they targeted is dense, and the area was heavily trafficked during the Labor Day holiday weekend.

Some of Wednesday's searchers are from the organization Destiny's Search, which worked on both the Elizabeth Smart and Lori Hacking cases.

Investigators have been on the lookout for Cleverley's purple and silver Schwinn bicycle, which is also gone. She didn't have her cell phone with her, police told FOX, but was apparently carrying her wallet and keys.

Her mother, Susan Cleverley, said Wednesday that her daughter's messages since the disappearance have been scanned, but they were all just from people expressing their concern.

The chief of police cautioned against drawing any hasty conclusions, saying detectives hadn't focused on any one theory as to what may have befallen the student.

"Right now I'm saying we just don't know" what happened to Camille, Provo Police Chief Craig Geslison told FOXNews.com on Tuesday. "We really don't have anything specific ... We're just looking at everything at this point in time."

Investigators have combed through Camille Cleverley's apartment, the bike trail she frequented and other areas around campus where she worked and was known to go, he said.

The chief said his department was collaborating with the Utah County sheriff's office in expanding the hunt for Cleverley.

On Tuesday afternoon, a fixed-wing surveillance plane flew over Rock Canyon, where Cleverley was known to spend time, but found nothing. A group of volunteers with search and rescue dogs also scoured the canyon.

Camille's family was holding onto hope that she is still alive.

"I think she's probably hurt somewhere," said her mother.

The blond, fair-skinned college student was last seen on Thursday, most likely by a roommate, according to Geslison.

"Her bicycle is missing, so we assume that she had taken off on a bike ride," her mom told FOX News. "She had been visiting with us the previous weekend and had left her cell phone at her sister's."

Camille would have started classes at Brigham on Tuesday. The university sent out an e-mail alert to students and faculty Tuesday informing them of the disappearance.

"BYU is obviously very concerned and hopeful," spokesman Michael Smart said. "We are taking our lead from Provo police as to how we can support their search efforts. Students have been involved passing out fliers."

Camille hasn't shown up to work at the university in recent days, though Friday is her day off.

"She's a very reliable person," said Susan Cleverley. "She has not been at work for the days that she's been scheduled, and that's very unlike her."

The young woman's boyfriend has been very cooperative in the investigation, according to police and her family.

"He's been very supportive," her mother said.

She added that the family wasn't aware of any reason her daughter might have run off or sought some time alone. Geslison echoed those sentiments, saying he didn't know of any emotional or other problems Camille was having that would cause her to leave suddenly, without a trace, the way she did.

"We're just looking at everything at this point in time," he reiterated.

Camille's family has also been helping in the investigation and they were the ones who notified police of her disappearance — after her roommates apparently contacted them when she didn't come home, according to the chief.

Though numerous tips have poured into the Provo Police Department, no one has called to say they have seen a young woman matching Camille's description, according to the chief. And no one knew of any plans she had to go away for the long holiday weekend.

As far as whether foul play might be involved, the missing student's mother and police both said they didn't have enough information to go on.

"We have no idea," said Susan Cleverley. "(Police) have several diff scenarios that they’re working on. Right now, we’re trying to get a lead on any one of them."

Cleverley lived in an off-campus apartment and had just met her new roommate before she disappeared, her brother David Cleverley said.

"It could be anything from her getting hurt and lost to an abduction. It's been tough," said 24-year-old David Cleverley, a student at Utah State University in Logan. "It's frustrating to try to put it all together because we have nowhere to start. We don't know what she was thinking when she left."

His sister had her contact lenses with her but did not take eye solution or glasses, he said.

Cleverley is white with strawberry blond hair, blue eyes and fair skin. She's 5 feet 5 inches tall and 110 pounds. Police are asking anyone with any information to call (801) 852-7241 or (801) 852-6210.

FOX News' Catherine Donaldson-Evans and The Associated Press contributed to this report.