Police waited to enter Texas school as shooter went on killing spree: witness

The teenage madman who slaughtered 19 kids and two teachers in a Texas school spent more than 40 minutes inside as witnesses desperately urged police to charge into the building, it was ­revealed Wednesday.

Salvador Ramos barricaded himself inside the classroom before opening fire on students and teachers inside. Border Patrol agents finally breached the door about 40 minutes to an hour later when a staff member gave them a key.