PRESTON, Minn. – Mostly rural Fillmore County hasn’t escaped the torrent of catalytic converter thefts from parked cars. Fillmore County Sheriff’s investigator Dan Dornink said dozens of convertres have been cut from under automobiles since fall. “It all comes down to supply and demand,” Dornink said in a KIMT television interview. Converters are pollution-control devices designed around the rare metal palladium.The scrap value of a converted at junkyards, Dornink said, can be as much as $500. Most thefts have been in the early morning and late at night, he said. Converter thefts have been a problem also in Winona, Rochester and LaCrosse. Thirteen were reported in Rochester this week.