Former student opens fire at Florida high school, killing more than 15 people

Family member embrace following a shooting at Marjory Stoneman Douglas High School, Wednesday, Feb. 14, 2018, in Parkland, Fla. (AP Photo/Wilfredo Lee)

Waiting for word from students anxious family members gather at Coral Springs Drive and the Sawgrass Expressway, just south of the campus ,following a shooting at Marjory Stoneman Douglas High School in Parkland, Fla., Wednesday, Feb. 14, 2018. (Amy Beth Bennett/South Florida Sun-Sentinel via AP)

Students are evacuated by police from Marjory Stoneman Douglas High School in Parkland, Fla., on Wednesday, Feb. 14, 2018, after a shooter opened fire on the campus. (Mike Stocker/South Florida Sun-Sentinel via AP)

Parents wait for news after a reports of a shooting at Marjory Stoneman Douglas High School in Parkland, Fla., on Wednesday, Feb. 14, 2018. (AP Photo/Joel Auerbach)

PARKLAND, Fla. — A former student opened fire with a semi-automatic rifle at a Florida high school Wednesday, killing at least 17 people and sending hundreds of students fleeing into the streets in the nation’s deadliest school shooting since a gunman attacked an elementary school in Newtown, Connecticut.