A protester takes shelter Wednesday from smoke billowing around him in Ferguson, Missouri. Protests in the St. Louis suburb rocked by racial unrest since a white police officer shot and killed an unarmed black teenager turned violent Wednesday night, with some people lobbing Molotov cocktails and other objects at police, who responded with smoke bombs and tear gas to disperse the crowd.

Ferguson Police Chief Thomas Jackson, who has been the public face of the city torn by Saturday’s death of 18-year-old Michael Brown, told reporters earlier in the day that the St. Louis County investigation of the shooting could take weeks to complete. In the meantime, he said, his department welcomes Justice Department training on racial relations in the suburb, where two-thirds of the 21,000 residents are black while all but three of the police force’s 53 officers are white.

“Unfortunately, an undertow (of racial unrest) has bubbled to the surface,” said Jackson. “Race relations is the top priority right now.”

Jackson has faced mounting demands from protesters, clergy and even hackers to reveal the identity of the officer who shot Brown. Jackson argues that revealing that detail could bring retribution to the officer. Jackson said Wednesday that the officer involved sustained swelling facial injuries.

— The Associated Press