Another night of violent protest in Ferguson, Missouri, with police firing tear gas and smoke canisters to disperse the crowd.

The violence erupted hours before a curfew - imposed for a second night - was due to come into effect.

The St. Louis suburb has been hit by racially charged demonstrations since an unarmed black teenager, Michael Brown, was shot to death on August 9th by white police officer Darren Wilson.

Sunday's protests were also fueled in part by news that a preliminary private autopsy had found Brown to have been shot at least six times, twice in the head.

Protester Key Smith says he came out to show support for Brown's family.

(SOUNDBITE) (English) PROTESTER KEY SMITH SAYING:

"It was a peaceful demonstration and I'm still trying to figure out why they would try to shoot the tear gas when they were just peacefully walking and protesting,"

But at a late night news briefing, State Highway Patrol Captain Ron Johnson defended the poli