IMPERIAL, Mo. (AP) — A 56-year-old Jefferson County man has been sentenced to 16 years in prison after pleading guilty to second-degree murder in his estranged wife's death. Matthew McDonough of Imperial pleaded guilty in Jefferson County Circuit Court to the death of his former wife Deborah. The couple was going through a divorce and Deborah McDonough was living in St. Louis when she was killed in July 2012 at their former home.