Pei Du
Shortly after, Wu Yuanheng was assassinated — probably by assassins sent by Li — and another official who advocated for the campaign against Wu Yuanji, Pei Du, was nearly also killed. Suspicions fell on eight Chengde officers stationed at Chang'an, headed by Zhang Yan (). Wang Chengzong's uncle Wang Shize himself reported that Zhang and the other Chengde officers must be responsible. The Chengde officers were arrested and interrogated by Pei Wu and the imperial censor Chen Zhongshi (). Under intense interrogation, probably including torture, Zhang and the others confessed to assassinating Wu Yuanheng and were executed. In fall 815, Emperor Xianzong issued an edict declaring Wang's guilt and refusing to accept his tributes, but not declaring a campaign against Wang by this point; rather, the edict called on Wang to examine himself and repent.