ST. LOUIS -- A former St. Louis sheriff's deputy who is seeking office has filed a lawsuit accusing the sheriff's department of racial discrimination.

Johnnie Chester filed the lawsuit Tuesday in St. Louis court against Sheriff James W. Murphy alleging a "pattern and practice" of racial discrimination in the department. Chester, who is black, alleges unequal pay and professional advancement based on race.

Chester is among five men now seeking to replace Murphy, who is white and not seeking re-election, The St. Louis Post-Dispatch reported. Murphy has been sheriff since 1989.

Murphy's executive aide, Michael Guzy, said neither he nor the sheriff could discuss the lawsuit because they had not been served in the case yet.

In 2010, two former deputies won a lawsuit accusing Murphy of running a racially hostile department, saying he didn't discipline employees who hung a noose from pipes near a prisoner holding area in the St. Louis Civil Courts building.

Chester has been a deputy for the department since 1993. It is unclear when and why he left, but Guzy said Chester hasn't been a deputy "for some time now."

In 2014, Chester also filed a charge of discrimination with the Missouri Commission on Human Rights while he still was employed. He received a notice of his right to sue from the commission in April.

St. Louis is an independent city that also acts as a county, which makes the sheriff's department necessary. The department's main role is courthouse security, in addition to prisoner transport and juror protection.