The Cook County Sheriff’s Office is mourning the loss of one of their own, Captain Terry "turtle" Arnold.

CCSO says that Arnold suffered an apparent fatal heart attack after dispersing a fight between two students that occurred at Cook County High School.

Captain Arnold, with the assistance of school administration, had taken a juvenile involved in the fight into custody and was exiting the main entrance of the school when he collapsed.

School medical personnel and responding backup immediately rendered aid until the arrival of emergency medical services.

He was transported to South Georgia Medical Center where he was pronounced dead a short time later.

Captain Arnold just completed his 26th year at the Cook County Sheriff’s Office where he had served in every facet of the office including his current assignment as supervisor and director of the School Resource Officers Division for the sheriff's office and the Cook County School System. He had previously served the City of Adel and City of Remerton Police Departments as well.

Captain Arnold is survived by his son, four daughters, and ten grandchildren, as well as countless friends, family, coworkers, and colleagues.

Officials say that Arnold's death is the first recorded line of duty death in the history of the Cook County Sheriff’s Office.

At this time, arrangements have not been made but will be announced soon.