By Rob Alway. Editor-in-Chief. LUDINGTON — The mother of the man who killed Michigan State Police Trooper Paul Butterfield entered a plea in 51st Circuit Court this afternoon. Tammi Spofford, the mother of Eric John Knysz, pleaded no contest to accessory after the fact. Spofford, 50, of 8124 W. Eight Mile Road, Irons, was arrested last fall for her involvement…