Authorities say 65-year-old Jimmy Lee Dykes shot and killed a bus driver last week in Midland City and then abducted the boy.
Dykes is now dead, the source says, but the boy is in stable condition. An ambulance was seen leaving the area of the bunker.
The FBI said in a statement Sunday that authorities were having open lines of communication with Dykes. The little boy requested Cheez-Its and a red Hot Wheels car, both of which were delivered to the bunker, a separate statement said. Authorities had said they also were delivering medicine and other comfort items, and that Dykes was making the child as comfortable as possible.
On Sunday, more than 500 people paid final tribute to the driver that was killed, 66-year-old Charles Albert Poland Jr., hailing him as a hero for protecting the other children on the bus.
Poland is now "an angel who is watching over" the little boy, said Dale County School Superintendent Donny Bynum, who read letters written by three students who had ridden on Poland's bus. "You didn't deserve to die but you died knowing you kept everyone safe," one child wrote.
Outside the funeral, school buses from several counties lined the funeral procession route. The buses had black ribbons tied to their side mirrors.
Dykes grew up in the Dothan area. Mel Adams, a Midland City Council member who owns the lot where reporters are gathered, said he has known Dykes since they were ages 3 and 4.
He said Dykes has a sister and a brother, but that he is estranged from his family.
Adams said he didn't know what caused the falling-out, but that he knew Dykes "had told part of his family to go to hell."
Dykes, also described as a loner who railed against the government, lives up a dirt road outside this tiny hamlet north of Dothan in the southeast corner of the state. His home is just off the main road north to the state capital of Montgomery, about 80 miles away.
Government records and interviews with neighbors indicate that Dykes grew up in the Dothan area and joined the Navy in Midland City, serving on active duty from 1964 to 1969. His record shows several awards, including the Vietnam Service Medal and the Good Conduct Medal. During his service, Dykes was trained in aviation maintenance.
At some point after his time in the Navy, Dykes lived in Florida, where he worked as a surveyor and a long-haul truck driver. It's unclear how long he stayed there.
He had some scrapes with the law there, including a 1995 arrest for improper exhibition of a weapon. The misdemeanor was dismissed. He also was arrested for marijuana possession in 2000.
Dykes returned to Alabama about two years ago, moving onto the rural tract about 100 yards from his nearest neighbors, Michael Creel and his father, Greg.
"He said he lived in Florida and had hurricanes hit. He wanted someplace he could go down in and be safe," Creel said. Authorities say the bunker is about 6 feet by 8 feet, and the only entrance is a trap door at the top.
Neighbors described Dykes as a man who once beat a dog to death with a lead pipe, threatened to shoot children for setting foot on his property, and patrolled his yard at night with a flashlight and a firearm. Michael Creel said Dykes had an adult daughter, but the two lost touch years ago.
The Dykes property has a white trailer which, according to Creel, Dykes said he bought from FEMA after it was used to house evacuees from Hurricane Katrina. The property also has a steel shipping container -- like those on container ships -- in which Dykes stores tools and supplies.
Next to the container is the underground bunker where authorities say Dykes holed up with the 5-year-old. Neighbors say that the bunker has a pipe so Dykes could hear people coming near his driveway. Authorities were using the ventilation pipe to communicate with him.
The mother of the 5-year-old boy was 'hanging on by a thread,' said a local politician who visited the woman during the standoff.
State Rep. Steve Clouse, who represents the Midland City area, said the mother told him that the boy has Asperger's syndrome as well as attention deficit hyperactivity disorder, or ADHD.