Midland City, Alabama (CNN) -- Law enforcement officers were able to see what was going on inside the underground bunker where a 5-year-old boy was held hostage for a week with a camera they somehow slipped into the hideout, a law enforcement official said Tuesday.

As the standoff dragged on, an FBI hostage rescue team practiced on a nearby mockup of the bunker until kidnapper Jimmy Lee Dykes' declining mental state forced them to move in Monday afternoon, law enforcement sources said Tuesday.

The resulting assault -- from the top of the bunker, according to a law enforcement source -- ended with Dykes dead and the boy, named Ethan, free. Authorities took him to the hospital for evaluation, where he remained Tuesday.

"He was running around the hospital room, putting sticky notes on everyone who was in there, eating a turkey sandwich and watching 'Spongebob'," Dale County Schools Superintendent Ronny Bynum said.

It was not immediately clear when Ethan might be released, according to school officials.

Authorities say Dykes abducted the young boy from a school bus January 29.

Dykes approached the bus and demanded that the driver hand over two children. Dykes killed driver Charles Poland as he blocked the aisle -- allowing children to escape from the back of the bus, then seized Ethan and fled to the bunker, according to authorities.

During the ensuing standoff, authorities were extraordinarily tight-lipped about what was happening, but said they were in contact with Dykes and said they believed he had not harmed the boy. He also allowed authorities to deliver food, medicine and at least one toy for the boy to play with, according to authorities.

The details about the law enforcement response to his abduction are the first provided by authorities about how they knew what was going on inside the bunker and why they decided to move when they did.

But many questions remain, including whether the Defense Department provided sensing equipment to aid in monitoring what was happening inside the bunker and why Dykes acted as he did.

"A big boom"

At one point Monday, Dale County Sheriff Wally Olson told reporters that Dykes had "a story that's important to him, although it's very complex."

But according to a law enforcement source, Dykes' mental state deteriorated in the 24 hours before the Monday afternoon rescue.

Experts from FBI units, including a crisis negotiation team, tactical intelligence officers and a behavioral sciences unit, had determined Dykes was in a downward psychological spiral, the source said.

At 3:12 p.m. (4:12 ET) on Monday, the FBI team went in.

One neighbor said he was outside when he was startled by the sound of an explosion.

"I heard a big boom and then ... I believe I heard rifle shots," said Bryon Martin, who owns a home near the bunker where Ethan had been held.

It was a loud noise that "made me jump off the ground," he said.

Authorities wouldn't say whether the blast was set off as a diversionary tactic or whether Dykes had planted explosives around the bunker.

While the law enforcement source said FBI agents went in through the top of the bunker, the source declined to say specifically how they breached the roof, how many agents were involved or whether Dykes shot himself or was killed by FBI gunfire.

A Dale County official told CNN that Dykes had been shot multiple times. The body remains "in the area" and will be examined by the county coroner before it is taken to Montgomery, Alabama, for autopsy by the Alabama Department of Forensic Sciences, the official said.

Olson declined to say whether the boy saw his abductor die.

"He's a very special child. He's been through a lot, he's endured a lot," he said.

U.S. Attorney General Eric Holder praised law enforcement for saving the boy.

"I thought the FBI action on this was exemplary and as I think details are shared, you will understand why I use the word exemplary," he said.

Bynum, the school superintendent, said FBI agents broke down in "tears of joy" after the rescue was complete.

"It was a relief on all our shoulders," he said.

The aftermath

FBI bomb technicians were sweeping Dykes' property Tuesday looking for explosives, according to FBI spokesman Jason Pack. Evidence teams will take over when they are done, Pack said.

While authorities have not said whether Dykes killed himself or if the team that stormed the bunker shot him, the FBI is sending a "shooting review board" from Washington to look into the incident, Pack said.

Olson said Tuesday he could not release much information about the case.

"It's still actually an ongoing investigation, and we still have a lot of work to do here," the sheriff said.

Meanwhile, students in Dale County returned to school. State officials brought in a bus to replace the one Poland had been driving, state school transportation director Joe Lightsey said. Not all of the kids on Poland's route were back on the bus Tuesday, Lightsey said, but those who were seemed upbeat and ready to get back to class.

"A friendly kid"

While Ethan recuperated Tuesday from his ordeal, school officials began planning a party to celebrate the boy's birthday and to honor Poland, the bus driver hailed by school officials as a hero.

While the party won't be ready by Ethan's 6th birthday, which is Wednesday, it will be held soon -- likely at the Dale County High School football stadium, Bynum said.

Ethan's elementary school principal, Phillip Parker, said teachers are eager to have him back and "wrap their arms around him."

"Everybody knows Ethan. He's a good kid, a friendly kid," Parker said.

FBI Special Agent in Charge Steve Richardson said Monday that Ethan was in a private area of the hospital, with heavy security.

"He is doing fine," said Richardson, who had visited the boy. "He's laughing, joking, playing, eating."

What's next for Ethan?

Relief that Ethan was safe was palpable in Midland City, but many questions remain about what comes next for him.

How does a 5-year-old heal from this ordeal? How does a youngster go on after witnessing his bus driver shot to death, then being dragged to an underground bunker by a gun-toting stranger? How will he deal with what he experienced the six days he languished in that hole and what he saw during the explosive rescue Monday that killed his captor?

"It's very hard to tell how he's going to do," said Louis Krouse, a psychiatrist at Chicago's Rush Medical Center. "On the one hand, he might get right back to his routine and do absolutely fine. But on the other hand, the anxieties, the trauma, what we call an acute stress disorder, even post-traumatic stress symptoms, can occur."

Someone who knows all too well what Ethan may go through is Katie Beers, who as a 10-year-old was held underground in a concrete bunker for two weeks by a New York man.

"I am ecstatic that Ethan has been retrieved safe and sound," said Beers, who recently released a book about her abduction. "As for my ordeal, I just keep thinking about the effects of it: being deprived sunlight, nutritious food and human contact. And how much I wanted to have a nutritious meal, see my family."

Beers says she still feels the effects of her kidnapping.

"The major issue that I have is control issues with my kids and finances," she said. "I don't like my kids being out of my sight for more than two seconds. And I think that that might get worse as they get older."

Details Emerge In Alabama Child Hostage Rescue