Did Missing Teacher Voluntarily 'Drop Out'?

A missing 23-year-old teacher, who has sparked a 10-day search by authorities, friends and family, was seen alive recently in New York, the woman's brother told ABCNews.com.

Dan "Wally" Upp said that his sister Hannah Upp, who went missing Aug. 29, according to police, was recently spotted in midtown New York City. Upp declined to comment on media reports that his sister was spotted checking her e-mail in an Apple store.

"It has been a huge sign of hope and encouragement to her friends and family, and our deepest wish is that she is found as soon as possible," he wrote in an e-mail from Japan, where he is stationed with the Navy. "We still have no idea what brought all this about or what the rest of the story is, and there is no point in speculating right now."

The sighting of Upp in Manhattan raises the possibility that she is not a victim of a crime and has voluntarily dropped out of sight.

"We just want her back safe, and we are waiting to welcome her home with open arms and open hearts with no judgment, no matter what," her brother said.

New York police told ABC News that there were no new updates in the case to report.

Hannah Upp, a second-year Spanish teacher at Thurgood Marshall Academy in Harlem, was last seen Friday afternoon, Aug. 29, in her apartment by a friend, according to police.

A teachers' union and the New York Police Department are offering a reward for help in finding the missing New York teacher whose sudden disappearance has left friends and family baffled.

The United Federation of Teachers is offering a $10,000 reward for information leading to Upp. New York police are offering their own $2,000 reward.

"Our thoughts and prayers are with Hannah and her family during this trying time," UFT president Randi Weingarten said in a statement. "We have reached out to her family, and the NYPD offering to help in any way we can."

The Portland, Ore., native's army of friends launched a massive search following her disappearance.

Upp's distraught mother, Barbara Bellus, has been keeping a vigil in her daughter's apartment.

"She is a bright, beautiful young woman and a dedicated teacher, who has so much to offer the world and an overwhelming desire to contribute to its betterment in any possible way," Bellus said in an e-mailed statement. "We cannot imagine what has taken her away, but we want her back, whatever the circumstances."

Upp's two roommates, a man and a woman, became worried about her last Sunday night when they hadn't heard from her, roommate Samantha Gallardo, 25, told ABCNews.com.

According to Gallardo, Upp's other roommate, fellow teacher Manny Ramirez, searched her room and saw that her purse, wallet, cell phone, ATM card and subway card were all there.

"My roommate woke me up and we went down to the police station. They didn't seem too concerned about it at first, but at 4 a.m. there were already detectives in our apartment," Gallardo said. "There's been police in our apartment since."

Upp is a friendly vegetarian who constantly experimented with new dishes, Gallardo said.

"[She's] quirky in a really endearing and wonderful way, and she has so many friends. She is always going to visit friends or having friends come to visit her," she said.

When they found out she was missing, Upp's network of friends from around the city and from her alma mater, Bryn Mawr College in Pennsylvania, sprang into action. Several flew in from out of town and plastered the city with fliers.

"It's really heartening to see this many people supporting us," Gallardo said.

Hannah Wood, 22, who describes herself as one of Upp's closest friends in New York, started a Facebook page devoted to finding Upp. The group already has more than 1,200 members.

"We called the hospitals, and on Tuesday evening we sent out a bulletin we had been e-mailing among her most intimate friends," Wood said. "I decided I would make a Facebook group, and I took out an ad on Facebook asking if anyone had seen her. ... That has proven a phenomenal way of getting the word out."

Sarah Caldwell, a 22-year-old publicist for a book publisher, used her contacts to get additional help in the search. By Thursday night, New York magazine had posted information about the missing Upp, and the New York Daily News and New York Post have both written stories about the "Teacher Vanish Mystery."

"Her very close friend called me in a panic and let me know what was happening. We were waiting to hear that the police were officially launching an investigation, so I sent the e-mail yesterday," said Caldwell, who attended college with Upp. "She was always supersweet and superwelcoming. She was pretty much the nicest person you'd ever want to know."

Upp's outgoing nature makes her disappearance even more confusing to her friends and family.

"I refuse to believe that she would run away without taking [her purse or clothes] with her. There's not clothing missing that would suggest she had packed for a trip," Wood said. "None of it makes any sense, which is so weird."

Despite the confusion, Upp's friends and family remain determined to find the missing woman.

"What we're trying to do is get the word out to as many people as possible to see if anyone can provide a missing piece," Wood said.

Even in light of the sighting, Upp's brother remains baffled.

"There is so much we don't know about what has happened and why," he said. "I feel very confident that anyone who knows Hannah and her personality would agree with me in saying that there must be a lot more to this than we can possibly know right now."