The FBI has announced a $25,000 reward for information leading to missing 11-year-old New Hampshire girl Celina Cass.
FBI agent Kieran Ramsey said at a Saturday afternoon news conference that the reward would also cover information leading to the arrest and prosecution of anyone responsible for Celina Cass' disappearance.
Celina has been missing since Monday night from her home in Stewartstown, N.H.
A member of the community has added another $5,000 to the reward pot, according to Assistant Attorney General Jane Young.
Stewartstown, which has a population of 900, is not a rich area, so authorities are hoping this reward could be a huge motivation for someone to come forward.
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," said Sgt. Brian Adams from New Hampshire Fish and Game to WMUR.
"We have done line searches, and we're having dive teams come in tomorrow to search bodies of water," said Young in a press conference 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," Young added.
Officials said that they have received 150 tips and this is still considered a missing persons case. 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 search. Stewartstown is just a mile from Canada.
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," said Stewartstown resident Shahannah Fuller.
Celina's mother and stepfather have not spoken to the media and 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," said family friend Kirsten Lyons. "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."
ABC News' consultant Elizabeth Smart, a survivor of abduction who was found nine months after being kidnapped, said that it's crucial that the family utilize the media in the search for their missing child.
"The early hours of any abduction is so important. I certainly can understand their shyness in wanting to reserve their privacy. Enough cannot be done in bringing a child home…it might be the media that brought them home. That's what brought me home, because my parents kept my story alive," Smart said.
Smart said that knowing that your family is doing everything possible to find you impacts a kidnapping victim.
"From the victim's perspective, I remember hoping and praying that people would not give up…I remember hearing some people calling my name. It was just a couple of days after I was kidnapped and knowing that people were out looking for me, knowing that people care about me, it can make all the difference...That gave me hope," she said.
The home where Celina disappeared from remains cordoned off with police tape. The family, along with the town, is being questioned by authorities. Smart said that as painful as it can be for the missing girl's family to be questioned by authorities, they must cooperate.
"I don't think any person can fully realize the pain that a family goes through unless they have experienced the same thing and so I think everything needs to be taken with a grain salt and just think of their daughter and of bringing their daughter home and if that's going to cross them off the suspect list..then I think they need to think of her and what's best and of bringing her home."
Brad Garrett, an ABC News consultant and a former FBI investigator, said that authorities typically start missing children's investigations by closely examining the family and then expand the investigation out.
"All behavior in a family is relevant when you're looking for a missing child. And if you have a parent, for example someone that has a history of domestic abuse or domestic violence, I would want to know everything there is to know about that."
Court documents obtained by ABC News reveal that Celina's stepfather, Wendell Noyes, 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.