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CLEVELAND — An FBI agent has described some of the conditions found inside a Cleveland house where three women were imprisoned for a decade, include a makeshift front-door alarm system and a heavy curtain shielding the second floor.

Special Agent Andrew Burke testified at Ariel Castro's sentencing Thursday.

Burke says bedroom windows were boarded shut from the inside with heavy closet doors. Burke says a door to one bedroom was modified with locks on the outside and the doorknob removed.

He says the house was divided in ways to make it more secure and to hide the existence of rooms.

Burke says alarm clocks were wired to the front door, and some rooms had ventilation only to the attic because of the boarded-up windows. There also were chains in the women's rooms.