The U.S. Justice Department says in a lawsuit that a Mississippi sheriff fired an employee because he had to be gone on military duty for extended periods.

Coahoma County Sheriff Charles Jones told The Associated Press on Tuesday the employee was fired for “insubordination,” not for taking military leave.

The department filed a civil lawsuit Monday against Coahoma County on behalf of Jason M. Sims Jr. of Batesville. The suit says Sims has served in the military 18 years, is a staff sergeant first class in the Army Reserve and teaches leadership classes at Fort Knox, Kentucky.

The suit says Sims started working for the Coahoma County Sheriff’s Department in October 2014 and told his bosses he would need to take military leave. It says Sims would give three or four weeks’ advance notice to request time off, and the sheriff’s office “demonstrated hostility” during a work evaluation given by Chief Deputy Fernando Bee in 2016.

“Bee informed Sims that the Sheriff s Office, through Jones, was upset with Sims’ military leave, and that Jones might not retain Sims if his military leave continued,” said the lawsuit.

The suit says Sims was fired in August 2018. It demands that he be rehired and paid lost wages.

Jones said the sheriff’s department is “definitely fighting” the lawsuit, which was filed in U.S. District Court in Greenville.

“We’re 100% confident that he didn’t get fired for anything that had to do with the military,” Jones said.

Jones said Sims violated work policies, but said he couldn’t discuss specifically what they were because of the lawsuit.