"Perhaps everything going well for so long made me conceited. When it came to Jiang Ke's prison break, I made a rookie mistake. Detective, can you guess what mistake I made?" Cheng Lingfei asked.
"You shouldn't have implicated Yang Zebiao," Miao Ying interrupted before Zhao Yu could speak. "You shouldn't have placed Yang Zebiao's DNA under Wu Fangfang's fingernails."
"That's right!" Cheng Lingfei nodded in approval. "As expected of Detective Zhao's police lover, you are right! Indeed, I went overboard. My original intention was to use Yang Zebiao's DNA to confuse you, so you wouldn't be able to see the real motive. Otherwise, when Wu Fangfang and Jiang Ke's photos appeared it would have been too obvious there was a conspiracy going on."