Four guards at a privately run jail have been indicted on reckless homicide charges accusing them of beating a female inmate to death.

The indictment issued this week also charges the four guards with aggravated assault against Estelle Richardson (search), 34, who died in 2004. A medical examiner determined that she died of a skull fracture and had broken rib and a damaged liver.

Corrections Corporation of America (search), which employs the four guards, said it has cooperated fully with the investigation. It said the four guards have been on administrative leave since Richardson's death.

CCA is the largest for-profit prison operator in the United States and has run the Metro Nashville Detention Facility under a contract with the city and the county since 1990.

A police investigation found that the guards used excessive force on Richardson the day before she died. The guards acknowledged there was an altercation but said no excessive force was used.

One of the guards indicted, William Wood, 27, who was in charge of the area where Richardson was housed, told The Tennessean newspaper that guards subdued Richardson with Mace and removed her from her cell so that it could be cleaned, but he saw no one strike her.

Richardson had been awaiting trial on two charges of food stamp fraud. CCA records show she was separated from other inmates because she had fought with others. The records listed her as mentally deficient.

Nashville attorney Blair Durham filed a civil lawsuit against CCA for $160 million in damages on behalf of Richardson's two children, ages 6 and 14.

CCA said it had conducted its own investigation into the allegations of the indictment, but spokeswoman Louise Gilchrest said the company would not comment further.

The other guards arrested are Jeremy M. Neese, 25, Keith A. Hendricks, 37, and Joshua D. Schockman, 24. Their bail was set at $25,000.