Prosecutors again summoned the chairman of Kumho Petrochemical Co. for questioning on Saturday over allegations that he created big slush funds and made unfair profits by using internal information. Park Chan-koo, a younger brother of Park Sam-koo, chairman of the Asiana Group which owns South Korea\'s second largest carrier Asiana Airlines, is suspected of having raised tens of billions of won in slush funds by falsifying records of transactions with contractors.