Located 26 miles east of Carlsbad, the Waste Isolation Pilot Plant, or WIPP, is a world first: a series of man-made tunnels 2, 150 feet underground, designed to accommodate radioactive waste.

FORBES: How Carlsbad got WIPPed

Late in the evening, the man had the child in some sort of underground bunker or storm shelter, and SWAT team members were communicating with him through a PVC pipe, CNN affiliate WSFA reported.

CNN: STORY HIGHLIGHTS

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.

CNN: FBI: Bombs found in Alabama kidnapper's bunker

The Alabama man who held a five-year-old hostage in an underground bunker for nearly a week was killed during a firefight with police, the FBI says.

BBC: Alabama hostage-taker died 'in firefight'

In February, members of the team rescued a 5-year-old boy from a small underground bunker where he was being held hostage by a 65-year-old man.

NPR: FBI: Agents Fell To Deaths Training Off Va. Coast