Ferguson, Missouri (CNN) -- The morning after a peaceful candlelit vigil for a teenager fatally shot by police disintegrated into violence and looting, the mayor of Ferguson, Missouri, called for calm.
"Obviously, the events of last night are not indicative of who we are," James Knowles said, adding that the chaos that erupted Sunday night in the St. Louis suburb was "not constructive" and was only "bringing down the community."
The evening began with people who wanted to honor and remember 18-year-old Michael Brown. Witnesses say that he was unarmed and his hands were in the air when a Ferguson police officer shot and killed him Saturday.
Authorities told a different story. The police officer tried to get out of his vehicle just before the shooting, but Brown pushed him back into the car, said St. Louis County Police Chief Jon Belmar.
Brown "physically assaulted" the officer, Belmar said, and the teen tried to get the officer's weapon. Brown was shot about 35 feet from the vehicle, the chief said, declining to provide more details.
"The genesis of this was a physical confrontation," he said, adding that his department has been called in to conduct an independent investigation.
Ferguson Police said its cars are not equipped with dashboard cameras.
Shell casings collected at the scene were from the officer's weapon, Belmar said.
Anger over the shooting gripped many in Ferguson. Some shouted at police who were at the vigil.
Stoic police in riot gear watched as young men knelt before them, hands up to symbolize surrender
But one officer can be heard on video yelling back, calling protesters "animals."
"We will stay out here as long as you are!" protesters screamed at police.
Demonstrators held their hands in the air and chanted, "We are Michael Brown." Others held signs that said, "No justice, no peace." Another sign read, "Police stops should not = dead kids."
The gathering became more intense as some people broke windows at a store and began taking things from it. They threw rocks and bottles. Gunshots rang out.
Antonio French, an alderman in St. Louis, said a QuikTrip gas station was looted and an ATM dragged out.
"This QuikTrip is where things started (Saturday) with this case, based on various accounts," French said.
The slain teenager and a friend were "accused of stealing gum from the store or some sort of cigarettes," the alderman said.