When local authorities fanned out this week into villages and factory towns around Guangzhou, they were not hunting criminals or political agitators. They were racing to deliver their vision of the truth--to "clarify the rumor about a clash between security personnel and a pregnant street vendor," as the state press put it.The town of Zengcheng had erupted in protests, with hundreds of migrant workers tipping over police cars, smashing windows, and torching government buildings.