The School To Prison Pipeline
Hundreds of schools across America have their own police forces.
Armed officers patrol corridors and playgrounds to keep order and protect teachers from the violent behaviour of some children.
But there's increasing evidence that their presence is being used to deal with minor misdemeanours in the classroom.
In the past these would have been dealt with by a telling off from the teacher; nowadays it can mean arrest and a criminal record for children as young as twelve years old.
Nina Robinson reports from Texas on how the heavy hand of the law in some US schools in criminalising the very young.