The Chinese man who stabbed to death the father-in-law of a US Olympic volleyball coach "acted out of despair over personal failures", state media said on Sunday. A police investigation in Tang Yongming's home city of Hangzhou, in the eastern province of Zhejiang, found that he had "lost all hope after a series of failures in his life and took his anger out on society", the official Xinhua news agency reported. Tang, 47, had "pinned all his hopes on his 21-year-old son" following two failed marriages and his resignation from his former job at a meter factory. But his son was given a six-month suspended prison sentence for theft in March, the agency said. It quoted Hangzhou police as saying they had confirmed Tang's identity from fingerprints and DNA tests. The police called Tang's case an "individual extreme activity" and said he had no prior criminal record. Tang jumped 40 metres to his death from Beijing's ancient Drum Tower on Saturday after he had stabbed two US tourists and a Chinese tour guide in the tower. The United States Olympic Committee (USOC) identified the dead US visitor as Todd Bachman, the father-in-law of US Olympic men's volleyball head coach Hugh McCutcheon. Bachman's wife, Barbara Bachman, suffered "multiple lacerations and stab wounds" in the attack and was in "critical but stable condition" at a Beijing hospital after eight hours of surgery, USOC said. Chinese officials on Sunday sought to reassure foreign visitors that they were safe in Beijing. Chinese President Hu Jintao also expressed his sympathy to US President George W Bush. The Beijing Olympic organizers (BOCOG) said in a statement that Beijing was a "safe city" and that police were "doing their best to provide a safe environment for all tourists, Chinese and international, during their travels in Beijing".