A Texas death-row inmate facing execution next year has sued a Panhandle prosecutor, alleging she is denying him access to DNA evidence that has never been tested and could prove he is innocent of murdering three people in 1993.

Henry Watkins Skinner alleges in his original complaint in Skinner v. Switzer that the refusal by Lynn Switzer, district attorney for the 31st and 223rd Judicial Districts, to release the biological evidence for testing violates Skinner’s 14th Amendment right to due process and his Eighth Amendment right to be free from cruel and unusual punishment. Skinner sued Switzer on Nov. 27 in the U.S. District Court for the Northern District of Texas in Amarillo.