By Rodger Baker On Aug. 4, four days before the start of the Beijing Olympics, two ethnic Uighurs drove a stolen dump truck into a group of some 70 Chinese border police in the town of Kashi in Xinjiang, killing at least 16 of the officers. The attackers carried knives and home-made explosive devices and had also written manifestos in which they expressed their commitment to jihad in Xinjiang. The incident occurred just days after a group calling itself the Turkistan Islamic Party (TIP) claimed responsibility for a series of recent attacks and security incidents in China and warned of further attacks targeting the Olympics. Chinese authorities linked the Aug. 4 attack to transnational jihadists, suggesting the involvement of the East Turkistan Islamic Movement (ETIM), which Beijing has warned is the biggest terrorist threat to China and the Olympics.