"It could range the whole gamut from 'I'm a runaway' to 'I've been abducted and killed,'" Knipes said.
But Dawn Drexel is adamant that her daughter did not run away.
"I think something has happened to her," Dawn Drexel told ABCNews.com earlier this month. "I just have a funny feeling. It's not like her to not call her family."
Drexel had been battling depression, her mother said, and had been recently put on medication. She had also been upset about family troubles, including the house that was in foreclosure and her mother's divorce from her stepfather who had raised Drexel since she was a small child.
Drexel had asked to go on the trip during her spring break from school with a group of older teenagers and young adults, but Dawn Drexel said no, sparking a fight between the mother and daughter.
"I just told her, 'No, I don't like the idea,'" Drexel's mother said. "I didn't know the people she was going with."
And, Dawn Drexel said, she didn't like the idea of her teenage daughter driving down to Myrtle Beach without a parent in tow.
Brittanee, she said, stormed off to a friend's house, saying she needed to cool down. She apparently defied her mother and went with her friends anyway.
Dawn Drexel said she didn't even know her daughter was in Myrtle Beach until her boyfriend called to say that her friends couldn't find her.
One of the last people to see Brittanee was her friend Peter Broswick, one of the Rochester men who Brittanee visited at the Bluewater Resort Saturday night. According to the police report, two of the men told police she stayed only for about 10 minutes and left to return some clothing to another friend.
Knipes told ABCNews.com that the men, including Broswick, checked out of their hotel between 1 a.m. and 2 a.m. that night and drove back to Rochester.
Broswick told ABCNews.com that he didn't have anything to do with Drexel's disappearance and that they'd been friends for about two years.
Broswick's lawyer, John Parrinello, told ABCNews.com that Drexel began hanging out with the men after having several disagreements with the friends she was traveling with.
After Drexel left the hotel, Parrinello said, the men went to a nearby college party but left shortly after. Since they had to check out of the hotel the next morning anyway, they decided to just leave then and get a head start on their trip.
"All of these innuendos and inferences are to no avail," Parrinello said.
Parrinello said the car the men had been traveling in haf been searched and Broswick was scheduled to give a DNA sample at the request of the Myrtle Beach police.