A former Cleveland school bus driver suspected of keeping three women captive for the past decade is to make his first court appearance.

Ariel Castro is due in a Cleveland courtroom for his arraignment Thursday morning on kidnapping and rape charges.

Police say they've talked with both Castro and the three women at length in building their case.

While they're not revealing many details, police do say the women were kept inside Castro's house for all but a brief few minutes over the last 10 years.

Police say what remains a mystery is how the women were kept in the house so long.

They got out of the house Monday when one made a daring escape out of a screen door and called 911.