A former Gwinnett County sheriff’s deputy turned himself in Monday to the Butts County jail on charges related to an inappropriate encounter with an inmate.

Terry Henderson, 40, is charged with violating his oath of office and engaging in illegal sexual activity during an inmate’s transport, Gwinnett sheriff’s office spokesman Shannon Volkodav said in a news release.

An inmate reported Henderson on Sept. 14, saying the deputy and she engaged in sex acts the day before, while he drove her from a facility in South Georgia to Gwinnett County.

Investigators determined the alleged activity took place in Butts County and presented the case to that county’s district attorney’s office, which determined there was sufficient probable cause to proceed with criminal prosecution.

Henderson was a 12-year veteran of the Gwinnett sheriff’s office before he was fired Sept. 26.

“His alleged behavior is inexcusable and offensive to the many men and women who proudly wear our badge and perform their duties each day with integrity,” Volkodav said.

Sheriff Butch Conway said he expects Gwinnett deputies to conduct themselves honorably.

“While I am extremely disappointed with the actions of Terry Henderson, I am mindful of the many deputies who serve our community each day with excellence,” Conway said.