Dad who killed kids: 'I know what I did was bad'

He held their heads under water in the bathtub, police say, until his three young children breathed no more.

Then, according to charging documents, Mark Anthony Castillo stabbed himself in the neck with a steak knife and downed 100 Motrin pills to try to kill himself before passing out near his children?s corpses in a 10th-floor room at the Baltimore Marriott Inner Harbor at Camden Yards.