Jeong Cheol
When the accusation against Jeong Yeo-rip was first made, the Easterners held key positions and were in charge of investigating the case. The Easterners told Seonjo that Jeong Yeo-rip could not possibly be plotting a rebellion when Jeong unexpectedly committed suicide, which was considered the admission of guilt. The Westerners accused the Easterners of being half-hearted in pursuing the case, and Seonjo promoted hardline Westerner Jeong Cheol as Right State Councillor and put him in charge of investigation despite Jeong Cheol's initial refusal. Soon afterward, Jeong Yeo-rip's nephew began to mention names of the Easterners including Left State Councillor Jeong Eon Shin, hardliner Yi Bal, and many others (It was customary to use to torture when interrogating prisoners). Their denial of being close to Jeong Yeo-rip angered Seonjo since many of their letters were found in Jeong's house, some of which were critical of the king and his rule. (It was said that Jeong Eon Shin was told by his men that his letters with Jeong were destroyed, but they only destroyed ones that directly mentioned his name and not nicknames. When Jeong Eon Shin denied exchanging letters with Jeong Yeo-rip, Seonjo angrily asked, "Does he think I have no eyes?" pointing to 19 letters in which they discussed state affairs.) Jeong Cheol asked for leniency with Jeong Eun Shin, Yi Bal, and others claiming that they could not know Jeong Yeo-rip's evil side, but the Easterners claim that Jeong Cheol sought to destroy them while appearing to try to save them on the outside. Indeed, Yi Bal and his brother, Choe Young-gyeong (greatly respected scholar of Yeongnam School), and many others died in prison of torture or illness. (Jeong Cheol's animosity with Yi Bal was such that he even spat on him in one occasion.) Even Yi Bal's 80-year-old mother and 8-year-old son were killed (although Jeong Cheol supposedly opposed it). The treason case went on for three years, and 1,000 people were killed or exiled. (According to some accounts, the death toll was 1,000.)