Cops: Girls Planned 'Mass Casualty Attack' on Texas High School

Two girls, ages 15 and 16, are accused of plotting a "mass casualty attack" on a high school in Texas, authorities say. The girls allegedly planned to use guns and pipe bombs in an attack on Memorial High School in the Houston suburb of Hedwig Village, KPRC 2 reports. The 16-year-old is former Memorial student transferred to an alternative school for students who fall behind, and the 15-year-old attends a different school, authorities say. The girls were arrested Tuesday within 30 minutes of the FBI informing law enforcement of what appeared to be a credible threat.

The 16-year-old has been charged making a terroristic threat, a third-degree felony. The 15-year-old is in custody on other charges. Spring Branch Independent School District Police Chief Larry Baimbridge says the teens had been planning the attack for "many weeks, if not months" and planning had "ramped up" in recent days, NBC News reports. He says it was a "clear plan" that went " well beyond just throwing some ideas around." Asked about possible motives, he said: "The only thing I was able to ascertain was there was just an overall disdain for her fellow students." (More Texas stories.)