He is Jimmy Lee Dykes, 65, a Vietnam veteran and retired truck driver who moved to the area about five years ago.
The sheriff's department released a photo of a gray-bearded, unsmiling Dykes and brief physical description: white male, 6 feet tall, weighing 170 pounds with brown eyes and gray hair.
Officials have been in "constant communication" with Dykes, Sheriff Wally Olson said Saturday. Dykes has told police that he has an electric heater and blankets for the boy. The sheriff publicly thanked Dykes for taking care of the child.
This much is known, according to police and witness statements: On Tuesday at about 3:40 p.m., bus driver Charles Poland Jr. was shuttling children from school to their homes when he dropped children off and the gunman boarded the bus.
The gunman demanded that Poland, 66, hand over two children. Poland refused, blocking access to the bus's narrow aisle as at least 21 children escaped out of the back emergency door, according to police.
The gunman shot Poland four times, killing him; grabbed the boy and then barricaded the two of them inside a nearby bunker.
It's unclear whether the gunman was after a specific child on the bus. Police have said there is no connection between the suspect and the abducted boy, whose identity is being withheld.
The suspect, who police have identified as Dykes, is holed up in a bunker 4 feet underground and built at least partially out of PVC pipe, authorities have said.
A hostage negotiator has been communicating with the alleged gunman through a 60-foot-long plastic ventilation pipe in an effort to end the standoff.
Authorities believe the boy is physically unharmed.