Man pleads not guilty to discarding human remains in Arizona January 13, 2021 GMT This booking photo provided by the Yavapai County Sheriff’s Office shows Walter Harold Mitchell, who faces charges of dumping body parts believed to have been used for medical research in remote areas outside Prescott, Arizona. (Yavapai County Sheriff’s Office via AP) This booking photo provided by the Yavapai County Sheriff’s Office shows Walter Harold Mitchell, who faces charges of dumping body parts believed to have been used for medical research in remote areas outside Prescott, Arizona. (Yavapai County Sheriff’s Office via AP) PRESCOTT, Ariz. (AP) — A man accused of discarding human remains in remote areas of central Arizona has pleaded not guilty in the case.