Yang Liang
In 604, Emperor Wen died—a death that traditional historians generally believe to be a murder ordered by his son and crown prince Yang Guang, although they admitted a lack of direct evidence. Yang Guang took the throne as Emperor Yang. Immediately thereafter, another son of Emperor Wen, Yang Liang the Prince of Han, rebelled against Emperor Yang at Bing Province (并州, roughly modern Taiyuan, Shanxi). Emperor Yang, for reasons not stated in historical accounts, suspected Dou of collaborating with Yang Liang and sent the general Li Zixiong (李子雄) rushing to You Province to arrest Dou and replace him. Li subsequently alleged that Dou had received letters from Yang Liang urging him to join the rebellion but had not reported them to Emperor Yang. However, after an investigation, Emperor Yang concluded that there was a lack of evidence that Dou collaborated with Yang Liang, but nevertheless removed him from governmental service and further stripped him of the title of Duke of Chen, bestowing that title on his younger brother Dou Qing (竇慶) instead.