(CBS/AP) MIDLAND CITY, Ala. - Authorities said accused kidnapper Jimmy Dykes rigged explosives in the underground bunker where he kept a kindergartner hostage and tried to reinforce it against any raid before SWAT agents stormed into the shelter to rescue the boy.
Officials said Dykes, 65, engaged in a firefight when authorities stormed into the shelter Monday, which led to his death and ended the nearly weeklong hostage ordeal. Relatives said the boy, who turns 6-years-old on Wednesday, appears to be doing well and is back at home.
Law enforcement officials only identified the kindergartner by his first name, Ethan, who was seized off a crowded school bus on Jan. 29 after Dykes allegedly shot the driver dead. He then took Ethan to the bunker where he was held until Monday's rescue.
An FBI statement late Tuesday said Dykes planted an explosive device in a ventilation pipe that he used to communicate with negotiators on his property in the rural Alabama community of Midland City. The suspect also placed another explosive device inside the bunker, the FBI added.
Dykes appears to have "reinforced the bunker against any attempted entry by law enforcement," FBI special agent Jason Pack said.
When SWAT agents stormed the bunker to rescue the boy from the man's property, Dykes "engaged in a firefight with the SWAT agents," Pack added.
Officers killed Dykes and whisked the boy to safety, said an official in Midland City speaking on condition of anonymity.
According to the FBI, bomb technicians scouring Dykes' property found the two explosive devices. Pack said the devices were "disrupted," though he did not say whether that meant they were detonated or disarmed.
Officers will continue to sweep the 100-acre property on Wednesday so investigators can investigate more thoroughly, Pack said.
For days, officers communicated with Dykes through a plastic pipe that rose up from the bunker, which was similar to a tornado shelter and apparently had running water, heat and cable television.
Authorities said on Monday that Dykes had a gun and appeared increasingly agitated, although it's unclear exactly how his behavior changed. The Midland City official said law enforcement agents were observing Dykes with some sort of camera, which is how they saw that he had a gun.
Pack declined to get into specifics, but confirmed that high-tech surveillance equipment was used during the police standoff.
Dale County Coroner Woodrow Hilboldt said Tuesday that he was not able to confirm exactly how Dykes died because the man's body remained in the bunker since the boy's rescue. An autopsy was to be conducted in Montgomery once the body was removed.
Ethan, who has Asperger's syndrome and attention deficit hyperactivity disorder, was said to be acting like a normal kid after his rescue. Officials said there was no indication that Dykes harmed the boy.
The boy was running around, playing with a toy dinosaur and other action figures, eating a turkey sandwich and watching "SpongeBob SquarePants," relatives and Dale County Sheriff Wally Olson said.
"We know he's OK physically, but we don't know how he is mentally," said Betty Ransbottom, the boy's grandmother. She added that she feared the ordeal would stay with the child the rest of his life.
The family was relieved and grateful for all the support in a community where ribbons, fliers and vigils all symbolized the prayers for Ethan's safe return. In a statement released by authorities, his mother expressed thanks for all the hard work of so many officers to bring her son home. During his captivity, his only comforts were a Hot Wheels car and other treats passed to him by officers. The woman declined to be identified, the statement said.
"For the first time in almost a week, I woke up this morning to the most beautiful sight ... my sweet boy," she said. "I can't describe how incredible it is to hold him again."
Children and teachers were trying to get back to normal, though some children who were on the bus where Dykes killed the driver on Jan. 29 have not yet returned to school, said Donny Bynum, superintendent of Midland City schools. Counselors and clergy are at the school to help any distraught students.
Officials hope to eventually throw a party to celebrate the boy's sixth birthday and to honor the memory of Charles Poland Jr., the slain bus driver hailed as a hero for trying to protect nearly two dozen youngsters on his bus. No date has been set, Bynum said.