(Reuters) – Investigators in western Kentucky on Wednesday were probing why a 15-year-old boy opened fire in a rural high school, killing two students and injuring 18 others in the latest in a series of deadly shootings in American schools.

Police have not yet identified the gunman or released any information about what motivated the Tuesday morning attack at Marshall County High School in Benton, Kentucky, about 120 miles (190 km) northwest of Nashville, Tennessee.

The suspect, who police said was arrested without a struggle, was due to appear in court by Thursday and could be charged as an adult, according to Marshall County Attorney Jeff Edwards.

He will be charged with two counts of murder and multiple counts of attempted murder, according to the Kentucky State Police, who said they believe he acted alone.

Students attend a prayer vigil for students killed and injured after a 15-year-old boy opened fire with a handgun at Marshall County High School, at Life in Christ Church in Marion, Kentucky, U.S., January 23, 2018. REUTERS/Harrison McClary

All classes were canceled in the Marshall County school system on Wednesday as the community struggled to understand the outbreak of violence.

“A tragedy beyond words occurred in our community today,” school Superintendent Trent Lovett said in a statement late Tuesday. “As parents, our greatest fear is something happening to our children, and today that fear became a reality.”

The suspect on Tuesday entered a common area at the school, pulled out a handgun and began firing at students, state police said in a statement.

The attack at the school of nearly 1,150 students in a small farming town was the latest outbreak of gun violence that has become a regular occurrence at schools and college campuses across the United States over the past several years.

The students killed were Bailey Holt, a 15-year-old girl who was pronounced dead at the scene, and Preston Cope, a 15-year-old boy who died at Vanderbilt University Medical Center, state police said.

“Bailey Holt and Preston Cope were two great people. I have never heard one negative thing come from their mouths,” Marshall County High student Gabbi Bayers said on Facebook. “It hurts knowing we won’t be able to share the laughs anymore.”

Police investigators are seen at the scene of a shooting at Marshall County High School in Benton, Kentucky, U.S., January 23, 2018. REUTERS/Harrison McClary

Five female and 13 male students 14 to 18 years old were also injured. Sixteen of the injuries were from gunshot wounds. The remaining four teenagers suffered other kinds of injuries in the panic.

Five victims were still receiving care at Vanderbilt University Medical Center in Nashville on Wednesday. Hospital officials said all were in stable condition.

(Reporting by Gina Cherelus in New York; Editing by Scott Malone and David Gregorio)