In response to a wrongful termination claim, Oklahoma County District Attorney David Prater reported Friday that he fired a chief investigator for "carrying out an improper sexual relationship with a subordinate."

He told state and county officials the "flagrant misconduct" by chief investigator William D. Muller "potentially exposed the State to civil liability."

The DA further told officials that Muller, a former Secret Service agent, was fired Jan. 29 for a pattern of dishonesty and for ineffectiveness as a supervisor and investigator.

Muller in October demanded $125,000 in damages for his termination after less than two years as Prater's chief investigator. He claimed he was fired after he failed to find any evidence against Prater's "political enemy," former House Speaker Kris Steele.