"I don't know why somebody would take her," Crystal Sheffield, the girl's mother, said at the time of her daughter's disappearance. "I'm scared for her. She is probably scared and cold and hungry."
Throughout the ordeal, Haleigh's family has shown similar dogged determination.
"If I lost hope, what does she have left then?" Ronald Cummings told ABC News' Orlando affiliate WFTV in February 2009. "Like I gave up on her? I'm not giving up on her. Never."
Florida police treated Haleigh's disappearance as an abduction, investigators said early on in the investigation, after concluding she did not simply wander off alone.
"All the world is a suspect," Det. John Merchant of the Putnam County Sheriff's Office told reporters at the time of her disappearance. "We are going to treat everybody, every family member, every associate, like a suspect until we eliminate them."
As police launched a massive search effort that included divers and K-9 units, Sheffield begged for her daughter's return.
"Whoever has her, I know you're watching," she told "Good Morning America" in February 2009. "She ain't done nothing wrong. Please bring her back."
In June 2009, vowing to leave no stone unturned, investigators dug up much of the 30-acre Glen St. Mary home of Haleigh's grandmother, Marie Griffis, but only recovered animal remains.
The Associated Press contributed to this report.