Special FBI Team Joins Hunt for Missing Girl

March 16, 2010 — -- The disappearance last summer of 10-year-old Lindsey Baum continues to haunt her family and her small hometown of McCleary, Wash., pop. 1,500. Now the FBI has stepped in, deploying an array of cutting edge law enforcement techniques in an effort to crack the mystery.

The girl, who would now be 11 years old, disappeared on the evening of June 26, 2009. Melissa Baum, Lindsey's mother, is convinced she was kidnapped.

"To the person or persons who stole my daughter," reads an open letter Baum wrote to the kidnapper she imagines. "Please let my daughter go. She needs her family. I don't care who you are, I just want my Lindsay back safely."

Watch the full story tonight on "Nightline" at 11:35 p.m. ET

Last month, ABC News accompanied local police and members of the FBI's Child Abduction Rapid Deployment (CARD) team as they worked on the case.

The task force questioned two-thirds of the town's residents. They also set up a massive command post with state-of-the-art equipment capable of tracking down leads around the country. An FBI computer database tracked leads as they came in and identified sex offenders who may have been in the area at the time of Lindsey's disappearance.

"Thousands of children go missing every year," said Kevin Perkins, assistant director of the FBI's criminal investigation division. "Many of them are runaways in family issues. But there's between 100 and 200 cases a year where it is a stranger abduction. These are very, very serious crimes that the FBI places a high priority on. There's no greater crisis in a community, and I can't imagine a greater crisis for either a parent or a community, then to have a child go missing."

The questions for the local police and FBI's CARD team: Was it an abduction? Or was it an accident? Where could Lindsay be now?

The model allowed the FBI to identify twelve new persons of interest in the case, inside and outside of McCleary, with at least two people of high interest.