Kidnapper 65-year-old Jimmy Lee Dykes was shot dead when police stormed the bunker in Midland City, Alabama.
He had kidnapped the child at random after shooting dead a school bus driver.
The boy’s great uncle, Berlin Enfinger, told reporters that the child was relieved to be home after his rescue a day earlier. Police said they considered the boy to be facing imminent danger when they decided to go in.
“He’s happy to be home, and he looks good,” Mr Enfinger said.
Authorities said little about the end of the stand-off. Neighbours said they heard a bang and gunshots. Authorities also kept under wraps exactly how they were able to monitor Dykes and the boy in such a confined space.
“We have a big crime scene behind us to process,” said Special Agent Steve Richardson. “I can’t talk about sources, techniques or methods that we used. But I can tell you the success story is (the boy) is safe.”
He declined to say if the property had been rigged with explosives.
Sheriff Wally Olson said that Dykes was armed when officers entered the bunker to rescue the child. He said the boy was threatened, but declined to elaborate.
“That’s why we went inside – to save the child ... it’s a relief for us to be able to reunite a mother with her child,” he said.
After the rescue the boy was reunited with his mother and taken to a hospital. He has Asperger’s syndrome and attention deficit hyperactivity disorder.
Authorities had been speaking with Dykes though a plastic pipe that went into the bunker which was about four feet underground, with about 50 square feet of floor space, built like a tornado shelter.
Neighbours said Dyke was an paranoid loner, who had been due in court for firing at cars in a row over a speed bumps and had once beaten a dog to death with an iron bar.