A prosecutor did not violate the due process clause when she failed to tell a murder witness who was later shot to death that the defendant allegedly was looking for a way to keep her off the stand, a federal judge held.In a written opinion, U.S. District Judge Steven C. Seeger of the Northern District of Illinois dismissed a lawsuit accusing Cook County Assistant State’s Attorney Victoria L. Klegman of creating a danger that Treja Kelley otherwise would not have faced and then failing to protect her from that danger …