Myron Wilkerson filed the suit March 11 in federal court in Evansville.
The Courier-Journal of Louisville, Ky., reports the 27-year state police veteran alleges he was removed from a wiretap investigation that he initiated in which all of the suspects were black.
The suit says after he filed a complaint with the Equal Employment Opportunity Commission he was charged with insubordination stemming from his verbal complaints about being removed.
The EEOC later dismissed Wilkerson's complaint.
State police spokesman Jerry Goodin declined comment on the suit.
Information from: The Courier-Journal, http://www.courier-journal.com