These so-called espionage cases are often used as a political tool to shift focus from domestic issues. Generally the truth doesn't matter. People will lose their interest quickly before the case reaches court. Few ever cared Wen Ho Lee was innocent, because he's a Chinese American (from Taiwan as well).
Both Chung and Chang are common spelling adopted in Taiwan. In mainland China and Singapore, where people use Hanyu Pinyin, Chung is spelt as Zhong and Chang as Zhang.