According to the FBI, bomb technicians scouring the Dykes property in southeastern Alabama found the two explosive devices.
The devices were "disrupted," Pack said, though he did not say whether that meant they were detonated or disarmed.
Officers will continue Wednesday to sweep the 100-acre property and, when they finish, investigators can more thoroughly investigate, 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.
On Monday, authorities said, Dykes had a gun and appeared increasingly agitated, though it's unclear exactly how his behavior changed. Negotiations — the details of which have not been made public — were deteriorating. The Midland City official said law enforcement agents had been 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.
Agents stormed the bunker. Neighbors said they heard what sounded like explosions and gunshots. Agents whisked the boy to safety and left Dykes dead.
Dale County Coroner Woodrow Hilboldt said Tuesday that he had not been able to confirm exactly how Dykes died because the man's body had remained in the bunker. An autopsy was to be conducted in Montgomery once the body was removed.
The boy, who has Asperger's syndrome and attention deficit hyperactivity disorder, was said to be acting like a normal kid after his rescue. And officials said there was no indication that Dykes had 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," Betty Jean Ransbottom, the boy's grandmother, told The Associated Press on Tuesday. She added that she feared the ordeal would stay with the child the rest of his life.