Alexander Hribal, a 16-year-old sophomore at the school, used a pair of eight-inch kitchen knives to stab and slash 20 students and a security guard.

[6] After stabbing several people, Hribal pulled a fire alarm, attempting to bring more students out into the hallway, according to witness testimony and surveillance footage.

One victim was placed on a ventilator after a knife pierced his liver, while another suffered an open wound to the face that required 11 sutures.

[15][25] He alleged that he was depressed, had suicidal thoughts during the fifth grade, and that those emotions returned while he was attending Franklin Regional High School.

[6] Several items belonging to Hribal were seized from his home, including a notebook with writing in it and a knife holder assumed to have held the two knives used in the attack.

[42][43][44] A hearing was held to determine whether the case would be transferred to juvenile court;[45][46] victims of the rampage testified about their injuries and urged the judge to try Hribal as an adult.

[47] In September 2015, a judge ruled that Hribal must be transferred from a juvenile detention center to Westmoreland County Prison when he turns eighteen years old.

[48][49] In June and November 2015, testimony statements were given by victims and defense experts in regards to the decision whether Hribal's case should be moved to juvenile court.

[52] On October 24, 2017, Hribal, then 20, pleaded guilty in the Westmoreland County Court of Common Pleas to 21 counts each of attempted homicide and aggravated assault.

Defense attorney Thomassey said that the Hribal family wished to spare victims from having to testify and relive the attack at trial.

[58] Following the incident, Pennsylvania Governor Tom Corbett visited Murrysville and held a press conference, during which he gave a speech praising the heroes of the rampage.

[28] On April 10, U.S. President Barack Obama called Franklin Principal Ron Suvak to tell him that the FBI would continue to assist in the investigation of the attack.