A federal lawsuit filed against Sigma Chi fraternity and University of Alabama football player Kelly Gregory Johnson alleges that Johnson assaulted a pledge at his home two years ago. The suit, filed against Sigma Chi Corp., the Iota Iota chapter at the University of Alabama and Johnson, states that fraternity members furnished alcohol to underage members. It claims that Johnson assaulted a pledge at a party, causing him serious physical harm. The personal injury suit was filed Friday in U.S. District Court in Birmingham. No criminal charges were filed against Johnson in relation to the alleged assault.