A Richland County jail officer is charged with killing his pregnant girlfriend, then setting her body on fire.

Sheriff Leon Lott said 23-year-old Tristan Gist was arrested Monday and charged with murder and death of a child in utero. Gist has been taken to the jail where he worked.

Coroner Gary Watts has tentatively identified the victim as 22-year-old Dierra Fisher, pending confirmation from medical records.

The sheriff's spokesman said Fisher was 21 weeks pregnant when she was shot in the head at their home about 3 a.m. Thursday.

Deputy Curtis Wilson said Gist drove her body to a wooded area, where he set her body on fire.

Wilson says Gist drove to the woods with Fisher's 2- and 3-year-old children, one of which is his as well.

The Associated Press contributed to this report.