Police used it to communicate with Dykes along with the telephone inside the bunker and the hatch door.

CNN: Inside the bunker: From storm shelter to boy's prison

It's possible the bunker has an escape hatch or door, officials said.

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One of Dykes' next-door neighbors said the suspect spent two or three months constructing the bunker, digging several feet into the ground and then building a structure of lumber and plywood, which he covered with sand and dirt.

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