MUNSTER, Ind. (AP) — A 14-year-old boy has died after being found unresponsive in a northwestern Indiana high school’s swimming pool.

Lake Ridge New Tech Schools’ superintendent says Curtis Walton was pronounced dead early Thursday at the University of Chicago Medical Center.

Dr. Sharon Johnson-Shirley tells The (Northwest Indiana) Times that Walton was found unresponsive at the bottom of a Calumet High School pool opened to the school’s football players following Wednesday’s practice.

Johnson-Shirley says trainers tried to revive Walton, who was a freshman member of the football team. He was taken to a Munster hospital before being airlifted to Chicago.

Johnson-Shirley says Walton’s death has devastated his family, school staff and students and “we’re just trying to make sense of what happened.”

The Lake County Sheriff’s Department is investigating the boy’s death.