Emergency crews rushed to Franklin Regional High School in Murrysville, Pennsylvania, on April 9 following reports of a knife attack. Dan Stevens of Westmoreland County Emergency Management Services confirmed that one security guard and 19 students were injured in the attack, four seriously. Those with injuries were taken to three local hospitals.

One person was reported to be in custody after accounts of a person running through the school slashing at students. Footage shows the scene shortly after the attacks. Credit: Instagram/Brandon Hudson