Stabbing at US high school leaves 20 injured

As many as 20 students in Pennsylvania high school victims of mass stabbing

A male suspect, believed to be a student, is being held in custody at the Franklin Regional High School in Murrysville, in the state of Pennsylvania, following a mass stabbing. 

The victims, aged between 14 and 17, were taken to hospital and four are said to be seriously injured.

The school was locked down while the police searched the premises.