KNOXVILLE, Tenn. (WATE) — An investigation is underway after six inmates in the Campbell County Jail are believed to have overdosed.

According to Sheriff Wayne Barton, around 1 a.m. on Oct. 11, six inmates were taken to LaFollette Medical Center after suspected overdoses. The inmates have since been treated and they are back in custody.

The substance that caused the overdoses is unknown at this time. The sheriff’s office is investigating the incident and trying to find out who supplied the inmates.

The jail is also going to be getting a body scanner to help with cavity searches within the next 30 days.