It appears the fatal fire in the Oregon County jail was intentionally set.

The State Fire Marshal’s Office has been called in to help in the investigation. Deputy Chief Fire Marshal Bill Zeires says the preliminary investigation indicates a mattress in a jail cell was set on fire. 17-year-old inmates Jessie Johnson died in the fire. An autopsy is being performed to determine the cause of death.

Three other inmates suffered serious injury. Eighteen-year-old Nicholas Pacheco, 19-year-old Cody Davis and 22-year-old Robert Huff are being treated at St. Johns Hospital in Springfield. All are on ventilators after suffering smoke inhalation.

Two other inmates suffered minor injuries. They were treated and released from the Ozark Medical Center in West Plains. A firefighter also had to be treated and released for injuries sustained in fighting the fire.

The Oregon County Sheriff’s Department states that a jail check at 9:23pm Thursday discovered nothing out of the ordinary. The fire alarm sounded and inmates began yelling at 9:40pm. The jailer reports that the smoke was too thick for him to enter the jail area. He requested assistance and emergency workers responded within five minutes.

A representative with the Fire Marshal’s office is traveling to Arkansas to talk with a person who was confined with the four the day before the fire was set.

Oregon County is located on the Arkansas border. Its county seat is Alton.