years in prison) 2000: Sexual abuse (rape) (sentenced 3 years 6 months in prison) October 27, 2000: Divorced by his wife September 11, 2003: Released from prison September 24, 2003: Killed first victims December 13, 2004: Sentenced to death 2023: Currently imprisoned (execution not yet carried out) Murders 1st, September 24, 2003, Gangnam-gu, Seoul: University professor Lee Deok-su, 72, was stabbed in the neck with a knife. He and his wife, Lee Eun-ok, 67, were then beaten to death with a hammer (4 kg). 2nd, October 9, 2003, Jongno-gu, Seoul: Kang Eun-sun, 85, was bludgeoned to death with a hammer. Her daughter-in-law, Lee Sook-jin, 60, and her handicapped grandson, Go Jin-soo, 35, were killed in the same manner soon afterwards. 3rd, October 16, 2003, Gangnam-gu, Seoul: Yoo Joon-hee, 60, was beaten with a hammer. She was later found by her son at 13:30 but died at 14:00. 4th, November 18, 2003, Jongno-gu, Seoul: Yoo used his hammer to kill Kim Jong-seok, 87, and the latter's housekeeper, Bae Ji-hye, 53. He then accidentally cut himself while attempting to open a safe, so he burned down the house to destroy DNA evidence. On December 11, 2003, Yoo met a new girlfriend (escort girl), but she inevitably discovered his criminal record and told him not to see her again. He then decided to kill escort girls as revenge. 5th, February 9, 2004, Namdong-gu, Seoul: Chung Young-dae, 47, was killed. 6th, March 16, 2004, Mapo-gu, Seoul: Yoo choked Kwon Jin-hee, 23, to death. He then cut her corpse into pieces and dumped them on a trail near Sogang University. 7th, April 14, 2004, Mapo-gu, Seoul: Ahn Jae-sun, 44, a vendor who had scammed Yoo by giving him fake viagra, was wrestled into his own van, handcuffed, and murdered. Yoo sawed the victim's hands off and disposed of them in a plastic bag. He then set the van on fire. 8th, May 2004, Mapo-gu, Seoul: Yoo lured 25-year-old Kim Hee-sun to his apartment and bludgeoned her unconscious with his hammer. He then decapitated her in his bathroom, smashed her head, mutilated her body, and buried her remains near Bongwon Temple in Seodaemun-gu. 9th, May 7, 2004, Mapo-gu, Seoul: Shin Min-a, 33, was killed in the same procedure as the 8th crime. 10th, June 1, 2004, Mapo-gu, Seoul: Han Sook-ja, 35, was killed in the same procedure as the 8th crime. 11th, June 9, 2004, Mapo-gu,