Anxiety and anger remained a toxic cocktail in the St Louis suburb of Ferguson last night as demands for the arrest of a police officer who shot and killed an unarmed black teenager 10 days ago grew louder and authorities sought to end nights of violence by sending in the National Guard.

Police in riot gear yesterday again fired tear gas to break up a crowd. Supported by an armoured vehicle and a helicopter, police repeatedly ordered the crowd to disperse.

They then let loose with a volley of tear gas, sending the crowd - smaller than the one that clashed with police on Monday - scurrying.

National Guard troops, carried in armoured vehicles, were ordered into the town by the Missouri Governor Jay Nixon on Monday after another round of violent clashes between police and protesters that erupted before the start of a midnight-to-dawn curfew. Schools were ordered closed.


Residents remained on edge, uncertain if the presence of the National Guard would discourage some demonstrators from venturing on to the battlefield that some of the town's streets have become, or compound distrust and a widely held sense that the grievances of a community distressed about the killing of one of its own have been met with a disproportionate response.

Another nervous shock was sent through the community with the release of a privately-conducted autopsy on the victim, 18-year-old Michael Brown, which showed that he had been shot six times and seemed to corroborate witness statements that he may have been trying to surrender at the time.

Earlier, Brown's mother, Lesley McSpadden, appeared on ABC TV News making clear her view that the police officer involved, who has been identified as 26-year-old Darren Wilson, should be arrested.

Asked how calm could be brought back to the town, she responded: "With justice ... arresting this man and making him accountable for his action."

Wilson remained in hiding yesterday, and St Louis County Police spokesman Brian Schellman did not respond to a query about why the officer had not been arrested.

The private autopsy found that the sixth and presumably final and fatal bullet fired at Brown entered the top of his head.

That, said family lawyer Daryl Parks, suggested that when he was killed, he was in a position of surrendering.

Poll race divide
Almost two-thirds of blacks - 65 per cent - surveyed by the Pew Research Centre last week said police went too far in their response to the Ferguson protests.

One-third of whites agreed, but nearly another third said the police response had been about right.

Gallup polling since 2012 showed that a majority of blacks, or 64 per cent, had limited or no confidence in the police, while the majority of whites, or 58 per cent, had a great deal or quite a lot of confidence.

Between 2009 and 2011, Gallup found 61 per cent of blacks had limited confidence in the police, while 62 per cent of whites had a lot of confidence in them.

- Independent, AFP, AP