Cai Lun
In 82, an opportunity came for Empress Dou. Consort Song, the mother of Crown Prince Qing, had become ill, and in her illness, she craved raw cuscuta, and she requested that her family bring her some. Empress Dou seized the cuscuta and accused Consort Song and her sister of using it for witchcraft. Emperor Zhang was enraged and expelled Crown Prince Qing from the palace. He had both Consort Song and her sister arrested and interrogated by the eunuch Cai Lun. Following this they committed suicide by poison. Crown Prince Qing was deposed and created the Prince of Qinghe instead; he was replaced by Prince Zhao as crown prince. Prince Zhao, however, was friendly to his brother, and they often spent time together.