A Rock Valley man accused of first-degree murder for strangling his wife is pleading not guilty.Fifty-one-year-old Phil Ter Maat entered the plea in Sioux County District Court yesterday. He was arrested August 1st after the body of his estranged wife was found on a nature trail in Rock Valley. An autopsy determined she had been strangled. He’s being held in the Sioux County jail on a half million-dollar bond. September 17th is the date set for his trial.