Two teenagers are under arrest for allegedly plotting what the FBI is calling "a mass casualty attack" at a Houston-area high school.

Two teenagers are under arrest for allegedly plotting "a mass casualty attack" at a Houston-area high school, the FBI said Wednesday night. The teen girls were accused of threatening to place pipe bombs and shoot their peers,

Two teenage girls arrested Wednesday evening are accused of posting online threats of an attack on a Spring Branch ISD school, authorities said.