A body found in a New Jersey river this week belonged to a 2-year-old girl whose remains were apparently stolen from a grave in Connecticut, police said Tuesday.

Two men fishing in the Passaic River on Sunday afternoon in Clifton, N.J., found a girl's body in a bag at the shoreline. An investigation led authorities to the grave of a girl who was buried in Stamford in 2007.

Authorities exhumed the grave and found an empty coffin.

Stamford Police Capt. Richard Conklin would not release the child's identity Tuesday but said authorities believe she was properly buried.

Police do not consider the girl's family suspects and said they appeared shocked to hear that their child's body was not in the grave, Conklin said.

"The Stamford Police Department's heartfelt condolences go to the family, who are reliving the grief of the loss of their child," he said.

The grave appeared undisturbed, but the coffin was damaged, an indication that the theft wasn't recent, he said.

He said police have no suspects and no clear motive. The body was in "remarkably good" condition, he said, and police were looking for any signs that it might have been used in a ritual.

"We have speculation and theories as to why something took place," he said.