No sooner after the dismissal bell rang at a western Pennsylvania high school Tuesday did shots ring out. In the chaotic aftermath, a student had been shot and police in McKees Rocks, Pa., were mounting an all-out search for the suspect, which continues today with all classes at Sto-Rox High School cancelled.

KDKA-TV reports that the shooting occurred about 2:15 p.m. Tuesday, and "there was one student shot by an unknown actor."

School officials tell KDKA that the incident took place as the high school students were being dismissed. About 40 to 60 students were lined up and getting on buses at the time. When they heard the gunshot, they ran back into the school.

Evidence at the scene included a cell phone and a shell casing were found on the sidewalk.

Police tell KDKA that the 17-year-old victim is expected to recover. His name has not been released.

Meanwhile the search for a suspect goes on, and while classes are cancelled today, counselors will be on hand in case any students need to talk about the incident.