WEST STEWARTSTOWN, N.H. — Two years after an 11-year-old girl vanished from her northern New Hampshire home and was found slain a week later, no arrests have been made, but prosecutors say the case is still active.

Celina Cass was reported missing after she was last seen using the family’s computer at about 9 p.m. July 25, 2011.

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Her body was recovered a week later from the Connecticut River, at a point a quarter-mile from her home.

Senior Assistant Attorney General Jane Young told the Caledonian-Record work has continued on the case. She said she is not at liberty to provide the details.

Young said she understands feelings of frustration in the community that no one has been arrested.

“Our goal has been to bring the killer or killers to justice,” she said. “But in a criminal case, we have only one opportunity to prove guilt beyond a reasonable doubt. We are always cognizant of that heavy burden.”

Prosecutors have labeled her death a homicide but have not revealed how she died.

Celina’s disappearance launched a massive search unprecedented in recent state history, with more than 100 law enforcement officials turning the Stewartstown Elementary School into a makeshift barracks. Searchers used police dogs and helicopters. A mobile cellphone tower was trucked in to enhance communications between teams in the field.

In the days following her disappearance, candles burned on picnic tables in a local park where children and adults held vigils to pray for Celina’s return. Friends said she was timid, a stickler for getting her homework done early and would not run away from home. But the vigils of hope turned into ones of grief.