WINONA, Minn. — A thief unbolted a catalytic converter from a car’s undercarriage sometime in a 15-hour window overnight. The theft was in the 100 block of Chatfield Street on the East Side. The theft was discovered about 9:15 a.m. Converters go for $500 to $800 on the blackmarket for their precious metal – either palladium, platinum or rhodium. The metal helps cut polluting tailpipe emissions.