By Jung Sung-ki Staff Reporter North Korean authorities have been investigating the chief of a North Korean committee in charge of inter-Korean economic cooperation for months after seizing $20 million from his house, a report said Friday. Quoting an unidentified Chinese source informed on North Korean affairs, the Dong-A Ilbo newspaper said Pyongyang authorities are intensifying their investigation into Jung Woon-eop and 80 other officials of the committee over where the money came from. South Korean experts on North Korea hinted that the money came from bribes paid by South Korean firms that are operating or want to operate in the joint industrial complex in the North's border city of Gaeseong, according to the newspaper. ``It could be the usual thing that those in power in North Korea, having poor banking agencies, keep cash in their house,'' an expert was quoted as saying. But he did not rule out the possibility of Jung and other officials in charge of cross-border business projects embezzling or diverting money from South Korean firms.'' About 65 South Korean companies are operating in the industrial complex with some 29,000 North Korean workers. The business complex, just north of the heavily fortified border, is considered one of the main achievements of the historic summit between the two Koreas in 2000. The zone is called a testing ground for mixing South Korean capitalism and technology with the North's cheap labor. gallantjung@koreatimes.co.kr