Several dozen protesters stood in the middle of West Florissant Avenue screaming at a line of police vehicles about a block away when suddenly some of them broke away and began looting stores.
Among the places hit was Feel Beauty Supply and Ferguson Market and Liquor, which had been previously boarded up and was the site of the earlier incident where Michael Brown was accused of stealing cigars. That incident took place shortly before he was fatally shot by a police officer.
Other protesters eventually lined up in front of the market, keeping looters from returning.
Car windows and the glass around at least one bus stop were smashed as a driving rain fell.
About 1:30, the police line appeared to be moving forward toward the protesters.