The latest in a series of violent attacks against Chinese citizens ended with the killer, Xie Yulin, 20, jumping to his death after hacking at six women in the southern city of Foshan, wounding five and killing one. It's the most recent in a spate of five grisly knife attacks, mostly against schoolchildren. A total of 17 have been killed in those incidents. The reason for the sudden increase in violence is unclear, although experts suggest that the attackers may be suffering from untreated mental illness. Furthermore, they say the stress of living in China's rapidly changing society may leave people feeing victimized, frustrated, and enraged. Guns are extremely difficult to get in China, so the killers, mostly men in their 30s and 40s, have used knives and hammers.