OWASSO, Okla. — A civil rights lawsuit filed against an Oklahoma city, its police chief and two state investigators is part of a nearly six-year legal fight with a police lieutenant who was fired twice amid excessive force allegations.

Owasso Lt. Mike Denton was fired in 2011 and 2015, the Tulsa World (http://bit.ly/2rlWiGx ) reported.

In 2011, the city settled a civil rights lawsuit filed by Bryan Scott Spradlin, a suspect who claimed he had been injured by Denton when he was arrested.

Denton also was charged with assault by Nowata County prosecutors in connection to the 2015 arrest of Cody Mathews, a stolen car suspect. Denton was later acquitted, but Mathews filed a civil rights lawsuit against Denton, which is still pending.

Denton was reinstated in both cases that alleged excessive force.

The lawsuit Denton filed alleges Owasso and Police Chief Scott Chambless retaliated against him for his “public employee union activities,” when requesting a probe by the Oklahoma State Bureau of Investigation. The suit also claims Chris Leamon and Kevin Lanham, two of the bureau’s agents, deliberately withheld evidence in order to support their filing of criminal charges.

It’s not clear how much money Denton is seeking in damages. The lawsuit doesn’t say.

A spokeswoman for the State Bureau of Investigation declined to comment to the newspaper on the pending case.

Information from: Tulsa World, http://www.tulsaworld.com