Two teenage girls arrested Wednesday are accused of plotting "a mass casualty attack" at Memorial High School in Spring Branch ISD, according to authorities. The Spring Branch ISD police department was initially notified by the FBI of a potentially credible threat against the school on Tuesday and arrested the student involved,

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

Evidence suggests their intent was to carry out acts of violence at a school in the Spring Branch Independent School District, law enforcement said.