Five people are in critical condition after deadly Kentucky high school shooting, police told reporters in Benton on Tuesday afternoon.

A 15-year-old boy opened fire with a handgun just before classes started at his high school in rural western Kentucky on Tuesday, killing two fellow students and injuring 19 other youths before he was arrested, the state’s governor and police said.

The shooter entered a common area at Marshall County High School in Benton, pulled out a pistol and began firing at students, witnesses told local media.

Authorities declined to discuss possible motives for the shooting. There was no immediate indication of how well the suspect knew the victims, but officials said he was believed to have acted alone and is expected to be charged with two counts of murder.