By Kathy McCormack, Associated Press

CONCORD, N.H. — It has been 18 days since Celina Cass’ body was found wrapped in a blanket at the bottom of the Connecticut River. The mystery surrounding her death and disappearance is growing. Even Celina’s father has no idea what happened to her.

“It makes me angry and frustrated because there’s nothing getting resolved,” Adam Laro said of the lack of answers.

Senior Attorney General Jane Young says investigators have researched 580 tips and continue to question many witnesses. They have not made any arrests. They have also not determined a cause of death and will not call Celina’s death a homicide.

WBZ-TV’s Lauren Leamanczyk reports

“What people want to know is, is there a child killer out there on the loose?,” WBZ asked at a news conference Thursday morning. Young answered, “at this juncture we are treating this as a suspicious death. We are doing everything we can to bring anybody to justice. People are reminded to remain vigilant until an arrest is made.”

WBZ NewsRadio 1030’s Mark Katic reports

The FBI and a private citizen are offering a 30 thousand dollar reward for information leading to the arrest and prosecution of whomever is responsible. Young announced that a reward fund has been established at Northway Bank in Gorham for citizens who want to contribute. She said several people have already called them asking if they can help.

Young insisted the reward does not mean the case is cold. Private investigator Don Nason who has worked with Celina’s family agrees.

“I think they know what’s going on, but they have to get that last piece of evidence to make sure they can do the right thing and make this prosecution stick,” he said.

Prosecutors compare the case to a puzzle. They hope the reward brings them the missing piece. Young said she understands people’s frustration.

“Sometimes as I indicated it may take longer than other times, but this is what we do and we’re in it for the long haul,” she said.

Autopsy results have been declared inconclusive until toxicology tests are returned. Young said that could take another week.