"It's way too early for that," said Kevin Cook, a spokesman for the Alabama state troopers.
Police have described the bunker as about 4 feet underground, with about 6-by-8 feet of floor space and the PVC pipe that negotiators were speaking through.
State Rep. Steve Clouse, who represents the Midland City area, said he visited the boy's mother and she is "hanging on by a thread." Clouse said the mother told him that the boy has Asperger's syndrome as well as attention deficit hyperactivity disorder, or ADHD.
Dr. Nadine Kaslow, a family therapist and psychiatry professor at Emory University in Atlanta, said the boy's emotional troubles might make things even more difficult for him.
"They have less way to make sense of things," she said of children with Asperger's and ADHD.
The normally quiet red-clay road leading to the bunker was busy Friday with more than a dozen police cars and trucks, a fire truck, a helicopter, officers from multiple agencies and news media near Midland City. The town, population 2,300, is about 100 miles southeast of Montgomery.
Police vehicles have come and gone for hours from the command post, a small church nearby.
Neighbors said Dykes was easily angered and 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.
He was in the Navy from 1964 to 1969, serving some time in Japan, according to military records.
Authorities said Dykes boarded a stopped school bus filled with 21 children on Tuesday afternoon and demanded two boys between 6 and 8 years old. When the driver tried to block his way, the gunman shot him several times and took the 5-year-old boy.
The bus driver, Charles Albert Poland Jr., 66, was hailed by local residents as a hero who gave his life to protect the pupils on his bus.
Dykes had been scheduled to appear in court Wednesday to answer charges he shot at his neighbors in a dispute last month over a speed bump. Neighbor Claudia Davis said he yelled and fired shots at her and her family over damage Dykes claimed their pickup truck did to a makeshift speed bump in the dirt road. No one was hurt.
Creel said his father and Dykes are friends. Creel said that after Dykes' arrest, Dykes wrote a 2- to 3-page letter that at least in part addressed the menacing case.
Michael Creel said he hasn't seen the letter but that his father, Greg Creel, has. Dykes reportedly told the elder Creel he had sent the letter to the local media, politicians and Alabama's governor.
Police on Friday took a copy of the letter from the Creels' home, according to Michael Creel. Reached for comment, Greg Creel confirmed the existence of the letter but declined further comment and said he was cooperating with police.
A neighbor directly across the street, Brock Parrish, said Dykes usually wore overalls and glasses and his posture was hunched-over. He said Dykes usually drove a run-down "creeper" van with some of the windows covered in aluminum foil.
Parrish often saw him digging in his yard, as if he were preparing to lay down a driveway or building foundation. He lived in a small camping trailer and patrolled his lawn at night, walking from corner to corner with a flashlight and a long gun. Authorities have not disclosed what firearms Dykes might have in his possession.