3 THINGS YOU NEED TO KNOW 1. A man, identified as 18-year-old Antonio Martin, was shot by a police officer in Berkeley, Missouri. 2. Authorities say the officer was responding to a reported theft when the man aimed a gun at him. 3. Crowds gathered at the scene and clashed with police. Fireworks and bricks were thrown.

A police officer fatally shot an 18-year-old man late Tuesday night at a gas station in Berkeley, Missouri, near Ferguson, after the man pointed a handgun at the officer, authorities said. A crowd then arrived at the scene and an intense clash broke out between protesters and police.

Police identified him as Antonio Martin on Wednesday morning. Martin was black; police said the officer who shot him was a 34-year-old white male, a six-year veteran of the Berkeley Police Department.

Authorities quickly laid out their version of events in a press conference Wednesday morning. They said the officer had arrived at the gas station to check on a reported theft and had started talking to Martin and another person.

Police released this surveillance video from the gas station, which ends when they say Martin raises a gun at the officer in the upper-left corner:

Chief Jon Belmar of the St. Louis County Police said his department had paused the public version of the video at that point, not showing the ensuing shooting, out of respect for Martin's family. He said more video would be forthcoming. The officer had been issued a body cam but had not clipped it on; his squad car's dash cam did not activate because the emergency lights had not been turned on.

In this image from the surveillance footage, police say the suspect is pointing a handgun at the officer.

The officer fired three shots, Belmar said. One struck and fatally wounded Martin, another hit the squad car's tire, and a third was unaccounted for. Martin did not fire his weapon, Belmar said. The second person fled, and police recovered a handgun at the scene. Some of Belmar's press conference Wednesday morning can be seen below:

"Bad choices were made," Belmar said. "This individual could have complied with the officer, he could have ran away, he could have dropped the gun."

Belmar did not initially identify the man who was shot as Martin, but he said he was "known to law enforcement" and had been arrested for three assaults, armed robbery, unlawful use of a weapon and other stealing charges since he was 17.

After the shooting, about 200 to 300 people arrived at the gas station, some of whom clashed with police. Belmar said police didn't use tear gas or flash bangs, but he said people in the crowd used three "explosive devices," likely fireworks. Two were thrown at the gas station, near the gas pumps, and one across the street at a convenience store, starting a small fire.

In addition, one person brought "a bag of rocks," and several bricks were thrown at officers, according to Belmar. "That's pretty disturbing," he said.

Police try to control a crowd Wednesday, Dec. 24, 2014, on the lot of a gas station following a shooting Tuesday in Berkeley, Mo. Image: St. Louis Post-Dispatch/David Carson/Associated Press

Four people were arrested for assaulting police officers during the fracas, Belmar said. One police officer was injured while trying to get away from one of the blasts, while another was hit in the face with a rock or brick.

Berkeley is about two miles from Ferguson, where a police officer fatally shot 18-year-old Michael Brown in August.

Belmar said the office of St. Louis County Prosecutor Robert McCulloch would determine how to proceed in the Berkeley case. McCulloch's office took the Ferguson case to a grand jury, which chose not to indict the officer who shot Brown.

See the latest live updates below.

Additional reporting by The Associated Press. This story is developing.