Police in Iowa have arrested a 47-year-old man who they claim admitted to killing his wife - a respected scientist - by sneaking up on her and stabbing her with a knife from their own kitchen. The Coralville Police Department said that Amber Nicole Martin, 41, a medical laboratory scientist supervisor of microbiology working at the University of Iowa Health Care, was found stabbed to death on Friday, January 16. Her husband, James Fuller Martin, has been formally charged with first-degree murder, according to The Gazette.