Police have said that there's no indication she ran away or that someone took her, and there are no signs of a struggle
But tight-lipped police investigators revealed little about the probe beyond that Wednesday, despite a flurry of activity in and around the three-story house where Celina lives with her mother and stepfather. Senior Assistant Attorney General Jane Young said it is still being treated as a missing persons case.
"We are still desperately looking for her," Young said.
She wouldn't comment when asked why an Amber Alert was never issued for the girl, even though the FBI said it had enlisted a four- to six-person "child abduction rapid deployment team" to pitch in. Earlier in the day, state police Sgt. Sheldon Belanger, the lead investigator in the case, said Celina's disappearance did not meet the criteria for an Amber Alert and wasn't considered suspicious.
Police were going through phone and computer records at Celina's home, he said.
Those who know Celina say it's unlikely she ran away.
"She never went anywhere without her mom or sister," said family friend Rebecca Goodrum, 30, fighting back tears and holding a lit candle Wednesday night at a vigil held in a park in neighboring Canaan, Vt., about a half-mile from the girl's home.
"She is very shy," said Kayla Baglio, 18, who knows her, too. "If she doesn't know you, she'd look at her sister to see if it was OK to talk to you."
Celina's friend, 11-year-old Makayla Riendeau, described the girl as very athletic and a stickler about getting her school work done on time.
"She's a very good friend, and she never lets anybody down," Makayla said.
Vermont State Police, the U.S. Border Patrol, New Hampshire State Police, the state Department of Fish and Game and local law enforcement agencies searched for the girl Tuesday and Wednesday, at one point resorting to lowering the water -- via dam release -- in the Connecticut River so a helicopter could search from above.
At the peak of the search Tuesday, there were at least three dozen officers, New England police dog handlers and a search and rescue group assisting by water, air and land, including all-terrain vehicle trails in the woods.
"We found no evidence that she had been in that area, and, of course, we have no evidence she is lost as opposed to missing, either," said Lt. Douglas Gralenski, a state Fish and Game official.
"Honestly, we don't know where else we can look," he said. "There's so much that's unknown."
At midday Wednesday, about a mile north of town, five Fish and Game officers searched the woods behind an apartment building. They carried bags and boxes, but it was unclear if they collected anything.
Some of the police activity was closer to home. Police were seen entering the home and then stretching yellow crime scene tape around it late Wednesday afternoon before posting a uniformed trooper outside.
After that, plainclothes police officers wearing purple rubber gloves surrounded a red pickup that was parked across the street from the girl's home, photographing it and looking inside. When news cameras began shooting pictures of what was happening, troopers moved a cruiser and a New Hampshire State Police SUV in front of the scene, to block the cameras.
The girl's disappearance hung heavy over Stewartstown, a community of 800 residents with one blinking streetlight and a handful of stores. Friends posted fliers of the girl on trees, utility poles, storefronts and car windows, and stood along the street in front of her house, waving motorists down to hand them copies.
"It's creepy," said Shannon Towle, who owns Towle's Mini-Mart on Route 3. "Things like this don't happen here. I know that's kind of a tired phrase. I'm an overprotective mom as it is. Now it's going to be way worse."
After sunset, about 80 people -- many with candles in hand and tears in their eyes -- gathered for the nighttime vigil. A framed picture of the girl sat on a picnic table, surrounded by candles. Friends, classmates and even people who didn't know Celina were among those in the crowd, and young children sobbed as adults comforted them.
Goodrum, of nearby Beecher Falls, Vt., said she was praying that Celina, whom she's known since she was 2, is safe.
"She was beautiful," said Goodrum. "She was the light of everything."
Towle said her 13-year-old daughter, Echo Towle, asked her mother whether she thought Celina was still alive.
"How do I answer that question? And do I want to?" Towle said. "I don't want to think about it, but I pray every second that she is."