Investigators working to learn how Floyd County inmate died

State officials are investigating after 55-year-old David Lee Daniel "unresponsive" in his cell. Jail staff and medical personnel rushed Daniel to a hospital but were unable to save his life, officials said. (Floyd County Sheriff's Office / FOX 5 Atlanta)

State officials are investigating after an inmate died in custody on Friday evening in Floyd County

The Floyd County Sheriff's Office said jail staff discovered 55-year-old David Lee Daniel "unresponsive" in his cell at around 11 p.m. on Friday. 

Jail staff and medical personnel rushed Daniel to a hospital but were unable to save his life, officials said. 

The cause of Daniel's death is unknown and the Georgia Bureau of Investigation will work independently to determine the circumstances surrounding the inmate's death. 

The GBI is conducting an autopsy at its crime lab.  

Officials said Daniel was arrested by Summerville police on Dec. 28, 2021 for theft by taking and misdemeanor simple battery on a law enforcement officer. 

A spokesperson said the Floyd County Sheriff's Office is fully cooperating. 

WATCH: FOX 5 NEWS LIVE COVERAGE