Graham, N.C. — A daylong search for a missing 7-year-old Florida girl who vanished on her way home from school Monday has produced more than 150 leads, but the child remained missing Tuesday and officials said they suspect foul play.

More than 100 Clay County, Fla., deputies, law enforcement officers from neighboring counties and the FBI scoured a residential Orange Park neighborhood looking for Somer Thompson.

"I can't describe how that feels. It feels like somebody just took the life out of you," said Sam Thompson, Somer's father.

Sam Thompson, an Iraq War veteran, lives in Graham, North Carolina. He is recuperating from an accident that left him in a wheelchair.

“For anybody who has taken my daughter, I would just beg them and plead to their sense of humanity that they would let my daughter come home,” he said.

Horses, dogs, divers and helicopters have been used in the search for the missing girl, which began Monday afternoon when she failed to return home from school.

Officials have no idea what happened to her.

The second-grader is white, 3 foot 5 inches tall and weighs 65 pounds. She had brown hair tied in a pony tail with a red bow and was carrying a purple Hannah Montana backpack and lunch box.

The Amber Alert was issued at 9 a.m. Tuesday by the Florida Department of Law Enforcement. The alert was not immediately issued for Somer because her disappearance wasn't witnessed and there was no description of a vehicle.

Law officers are working 12-hour shifts so they can search for the girl around the clock.