Investigators say the murder happened at the Northeast Correctional Complex in Mountain City.
They say the incident happened in the middle of a fight between several inmates.
Around 10 O'clock Saturday morning a 24-year-old inmate was pronounced dead.
They are not releasing his name until relatives can be notified.
As with all in-custody deaths, the Tennessee Department of Corrections has asked the TBI to assist in the investigation.
- Select children's tickets to be $10 for Cup Series events at Bristol Motor Speedway
- Public invited to give input on proposed hospital merger
- Mount Caramel police officer suspended on first day back to work
- Updated Voter registrars work to clarify restored voting rights
- Additional charges given to Sullivan County man charged with rape