Updated

An Alabama man who held a boy hostage in a bunker warned authorities some "very bad things" would happen if they didn't meet his demands, a sheriff said Thursday, shedding more light on the final moments of the standoff.

Dale County Sheriff Wally Olson said Jimmy Lee Dykes had two homemade explosives devices and authorities were worried he would set them off and kill the then-5-year-old boy. Officers raided the bunker Feb. 4 after a weeklong standoff and shot Dykes to death. The boy was rescued unharmed.

Olson said investigators still weren't sure of Dykes' motive.

"He kept saying he had a story that was very important to him and that he wanted to get out his story. But we've never been able to find out exactly what his story was. He would never really give us any insights into that," said Olson, who spoke to reporters after he gave a speech on gun legislation to lawmakers.

Investigators were reviewing writings found on Dykes' property to see if they offered any explanation into why he kidnapped the boy off a school bus Jan. 29, the sheriff said.

Dykes killed bus driver Charles Poland and took the child to an underground bunker near his mobile home. He had two explosive devices. One was set off in a PVC pipe but didn't harm anyone because authorities covered it with sandbags. The other device was more threatening, the sheriff said.

"If he had detonated that device, it would have killed him," Olson said of the boy. "We felt like his life was definitely in harm's way."

Dykes had been planning the event for weeks and became friendly with the bus driver, even clearing out a place close to his property where Poland could turn the bus around on the dead-end street.

Officers communicated with Dykes from the beginning by using the PVC pipe that led to the bunker. The sheriff said Dykes initially appeared focused on the child's safety, but that changed as the days passed and negotiations deteriorated.

He said Dykes gave officers a deadline to do things or else "some bad things would happen." The sheriff wouldn't say want those demands were.

Authorities, including the FBI and Alabama Bureau of Investigation, had developed different plans about what to do if that moment arrived, and they decided to act, he said.

The 40-year-old sheriff, who has two young daughters, said he handled the tense days with his children always on his mind.

"I don't want to look like a big boob and start crying. Now I do love my children, and I could only imagine what it would be like if that would have been my child. That's why I tried to do everything possible I could to make sure we had a safe return," he said.