Police admitted they had little physical evidence linking Yoo to the murders. Yoo first appeared in court on , refusing to defend himself, declaring his intention to boycott the remainder of the trial, and apologizing to the victims. Yoo boasted that he had no intention of stopping. When he was forced to return two weeks later, he lunged at the three presiding judges and recanted his confession for the February 2004 Imun-dong murder. He refused to appear at the next court session on , after attempting suicide the night before. Yoo again disrupted a hearing three weeks later when he tried to attack a spectator who had cursed him, which ended with Yoo signing a statement that he would not cause further commotion.