Florida ? Somer Thompson was last seen alive walking along the sidewalk in front of a vacant house, and authorities said Friday that they’re searching for anyone who saw what happened to the 7-year-old after that.

Her teary but resolute mother warned her daughter’s killer: “We’ll get you.” She pleaded for anyone with information to “please, please tell” police.

The day after the child’s body was identified, authorities said they had ruled out all 161 registered sex offenders who lived within a 5-mile radius of Somer’s home. Despite doggedly pursuing hundreds of leads, police have not made an arrest.

Investigators sifted through evidence from the vacant house and the Georgia landfill where her body was discovered Wednesday after investigators followed garbage trucks some 50 miles away from her neighborhood in suburban Jacksonville.