Police deny they have given up hope that missing 11-year-old New Hampshire girl Celina Cass will be found alive, and the state has asked for manpower and equipment from neighboring states to aide in the search.
In a news conference this evening, Celina's biological father, Adam Laro, spoke publicly for the first time, saying, "Come home. Whenever you are ready to come home, daddy is ready for you."
At the press conference, Assistant Attorney General Jane Young insisted that this is still a missing persons case. Additional aeronautical support has been brought in for the search, she said.
On Saturday, the FBI announced a $25,000 reward for information leading to Celina, and an anonymous member of the community added another $5,000 to the reward pot, Young said.
FBI agent Kieran Ramsey said Saturday the reward would also cover information leading to the arrest and prosecution of anyone responsible for Celina's disappearance.
The girl has been missing since Monday night from her home in Stewartstown, N.H., a town of 900 that is just one mile from the Canadian border. It is not a wealthy area, so authorities are hoping this reward could be a huge motivation for someone to come forward.
"It also could well be true that they just don't have any really viable leads on what happened or where Celina may be and they're hoping that the reward money will bring someone forward," ABC News consultant and former FBI agent Brad Garrett said.
"If someone has lured her away from her house, the odds of something bad happening are reasonably high," Garrett added.
Officials said that they have received 150 tips.
On Friday, at least 75 New Hampshire fish and game employees lowered the level of the Connecticut River and investigators searched frantically for Celina by helicopter, ABC Affiliate WMUR reported.
"We're looking for any clues, any disturbed ground, anything that will aid us in the search," Sgt. Brian Adams from New Hampshire Fish and Game told ABC affilate WMUR-TV.
"We have done line searches, and we're having dive teams come in tomorrow to search bodies of water," Young said Saturday evening.
Young would not comment on which bodies of water will be searched.
"If we're not going to leave any stone unturned we have to look in bodies of water as well as land areas," he said.
Celina was last seen Monday evening in her bedroom at her computer. Since then, more than 100 searchers including the FBI and the Royal Canadian Mounted Police have joined the effort.
New Hampshire authorities plan to talk to every person in the tiny town for clues about Celina's whereabouts.
"Every house, every individual in the neighborhood is being spoken to," New Hampshire Assistant Attorney General Jane Young said Thursday.
So far, this extraordinary effort has turned up nothing.
"I can tell you actually what we have not learned and that is where is Celina Cass now," FBI investigator Kiernan Ramsey said Thursday.
Ramsey remained hopeful.
"We're using advanced techniques from aviation to canines and the like. We are hopeful some positive outcome could result," Ramsey said.
The front lawn of the home where Celina lived with her mother, stepfather and 13-year-old sister has turned into a shrine of sorts, with candles, stuffed animals and notes to the missing fifth grader.
New Hampshire Town Searches for 11-Year-Old Celina Cass
Community members outside the home are flagging down cars and handing out flyers with Celina's image.
"It's a big world and she's a small girl and she's only 11. She doesn't know how to handle herself," Stewartstown resident Shahannah Fuller said.
Before today, neither Celina's mother nor her stepfather had spoken to the media and had requested "absolute privacy."
A family friend spoke for them Thursday.
"Celina is a young girl who is afraid and needs to be home with her family and friends," family friend Kirsten Lyons said. "We are pleading with anyone that has information to please contact the police. No piece of information is too small and every detail is very important. Celina is missed very much. We love her and we miss her smile and want her home."
Court Docs Reveal Past of Celina Cass' Stepfather
Court documents obtained by ABC News reveal that Noyes, Celina's stepfather, has a troubled past.
Noyes, 47, was involuntarily committed to a hospital in 2003 because of schizophrenia and arrested for threatening an ex-girlfriend, according to court documents.
Noyes was charged with violating a protective order held by his ex-girlfriend and for criminal trespassing, criminal threatening and hindering apprehension.
The girlfriend, who lived with her two kids at the time, said that Noyes broke into her home while she was sleeping, lifted her mattress and slammed it down and then threatened to throw her down the stairs.
While awaiting trial, a judge ruled Noyes incompetent to stand trial and ordered him to be involuntarily placed in a hospital. Judge Richard Hampe wrote that Noyes' mental illness creates "a potentially serious likelihood of danger to himself and others."
A forensic examiner deemed Noyes a paranoid schizophrenic who likely developed his mental illness while in the Air Force, according to court documents.
Noyes has not been named a suspect in the disappearance. No suspects have been named.
Celina is 5-foot-5 and weighs 95 pounds, with long brown hair and hazel eyes and was last seen wearing a pink shirt, a pink pullover, blue shorts and shoes.
If you have any information about Celina's whereabouts, call New Hampshire State Police at 603-846-3333.
ABC News' Ron Claiborne, Emily Friedman and Jessica Hopper contributed to this report.