Saitama Prefectural Police have been questioning a Chinese man arrested for allegedly running an underground bank and sending money illegally from Japan to China. Guo Tingyun, 37, was arrested Sept. 4 on suspicion of illegally remitting more than billion to China. Police believe he was sent to Japan by one of several Chinese corporate groups suspected of masterminding illicit money flows from Japan to Hong Kong and then on to mainland China.