Members of a group formed in memory of 16-year-old murder victim Lee Chae-won hold signs at a press conference outside the Gwangju District Court on Monday, calling for severe punishment for defendant Jang Yoon-gi. (Yonhap) A man charged with killing a teenage girl he did not know admitted Monday that the attack was intended as a sexual assault, abandoning his earlier claim that the killing was impulsive.Jang Yoon-gi, 23, pleaded guilty to all charges at his second hearing before the Gwangju District Court, including murder in connection with rape and the attempted murder of a teenage boy who tried to help the victim.Jang’s court-appointed lawyer told the court that Jang accepted the prosecution’s account of the crime. Asked by the judge whether he agreed, Jang answered, “Yes.”It was the first time Jang had admitted a sexual motive since his arrest on May 5.He had previously said he planned to take his own life and had tried to bring someone with him, saying that the killing had not been planned as a sexual offense.Prosecutors say Jang followed 16-year-old Lee Chae-won for about 15 minutes before stabbing her shortly after midnight near a university in Gwangju, about 270 kilometers south of Seoul. He also stabbed and seriously injured a 16-year-old boy who came to her aid.Police initially referred Jang to prosecutors on murder charges without alleging a sexual motive. Prosecutors later charged him with murder in connection with rape after conducting an additional investigation.Jang is also accused of breaking into the home of a 26-year-old foreign coworker two days before Lee’s death, sexually assaulting her and holding her captive for about 13 hours.He faces a separate charge of illegally filming women while serving as a social service worker.The court closed part of Monday’s hearing while reviewing video evidence because of the graphic nature of the case.