The immediate cause was a book called Sexual Customs (《性风俗》) published in 1987 which purported to describe the sexual life of Muslims and provoked some Hui people from Gansu, Ningxia and Xinjiang. The protesters, mainly Uyghur and Hui, initially conducted orderly march in the previous days and demanded for the government to destroy Sexual Customs and punish the book authors.[2] However, the protest ended up rioting, where nearly 2,000 rioters overthrew cars, smashed windows and some attacked staff at CPC office. The government dispatched 1000 policemen and 1200 armed police soldiers to disperse the crowd and arrested 173.[3]