Former student opens fire at Florida high school, killing 17

A former student opened fire with a semiautomatic rifle at a Florida high school Wednesday, killing at least 17 people and sending scores of students fleeing into the streets in the nation's deadliest school shooting since a gunman attacked an elementary school in Newtown, Connecticut.The shooter, who was equipped with a gas mask and smoke grenades, set off a fire alarm to draw students out of classrooms shortly before the day ended at one of the state's largest schools, officials said.Authoriti