ORANGE PARK - Somer Thompson was last seen alive walking along the sidewalk in front of a vacant house, and authorities are searching for anyone who saw the 7-year-old after that.
The day after the child's body was identified, authorities said they had ruled out all 161 registered sex offenders who lived within 5 miles of Somer's home.
Investigators sifted through evidence from the vacant house and the Georgia landfill where her body was discovered Wednesday after investigators followed garbage trucks 50 miles away from her neighborhood in suburban Jacksonville.
Somer vanished while walking home from her elementary school Monday afternoon. The vacant house is on her route through a heavily populated, well-manicured neighborhood. She had become upset as she walked with other children and ran ahead of the group. Somer never came home.
"What we've been trying to figure out is who frequents that area, because obviously it's more than just the people who live there," sheriff's spokeswoman Mary Justino said.
Neighbors said they were accustomed to watching out for each other's children as they walked to and from school.
"Everybody knows everybody here. If there was a stranger on the street, we'd be looking at watching where they were going, seeing what they were doing here," said Monica Loeb, a family friend.
At a vigil held outside the Thompsons' home Friday night, the mother said she would not be able to see her daughter's body.
"They are going to give me a lock of her hair," she said.