ORLANDO, Florida A Florida sheriff says the child's skull found near the Orlando home of a missing 3-year-old girl was "totally underwater" during previous searches for the toddler.
Orange County Sheriff Kevin Beary said Thursday investigators could not immediately say whether the remains belong to Caylee Anthony.
Beary says officials searched the surrounding neighborhood several times since she went missing in June. A utility worker found the remains Thursday morning.
Beary says FBI and forensic investigators will work through the weekend to identify the remains in what they consider a top-priority case.
Caylee's mother, 22-year-old Casey Anthony, has been charged with first-degree murder in connection with her daughter's death.
Authorities say they are seeking a search warrant for the Orlando home of missing Caylee Anthony.
Orange County sheriff's spokesman Carlos Padilla said Thursday that investigators cordoned off the home belonging to the grandparents of Caylee Anthony, who often stayed at the home with her mother.
Caylee's mother, 22-year-old Casey Anthony, insists that she left the girl with a baby sitter in June, but she didn't report her missing until July. The mother has been charged with first-degree murder.
The medical examiner left with the remains about 3 p.m.