Police say 16-year-old assailant used two knives in Pennsylvania school attack

MURRYSVILLE, Pennsylvania (Reuters) - The 16-year-old boy suspected of stabbing 20 people at his suburban Pittsburgh high school on Monday used two knives in the attack, Murrysville, Pennsylvania, police chief Thomas Seefeld told reporters.

Seefeld noted that a student or staff member at the school pulled the fire alarm when the attack began.

"The fire alarm being pulled probably assisted with evacuating the school," Seefeld said.

(Reporting by Elizabeth Daley; Writing by Scott Malone)