ST. LOUIS — St. Louis police used tear gas to disperse demonstrators and made nine arrests Wednesday night as protests continued over an officer-involved fatal shooting earlier in the day.

Police Chief Sam Dotson said protesters threw bricks and bottles at officers, and when they disregarded repeated calls to disperse, officers first used inert gas, and then tear gas.

He also said a car was set on fire and some businesses burglarized.

Police will maintain an increased presence at the intersection of Walton and Page, the site of the protests, throughout the night, Dotson said.

The shooting

During the day Wednesday, demonstrators played a cat-and-mouse game with police. They gathered at the intersection, dispersed, and then gathered again.

They were protesting the shooting death of an 18-year-old man by officers.

Dotson said two young men ran out of the back of a house when authorities arrived to carry out a search warrant.

“Officers in the rear alley ordered them to stop and to drop the gun. As they ran, one of the individuals turned and pointed the gun at the officers. There were two officers in the alley. Both officers fired,” the chief told reporters.

The suspect who allegedly pointed a gun at officers was struck, and pronounced dead at the scene.

He was not identified by name.

The protests

Soon after, protesters gathered at the intersection of Walton and Page, blocking the main thoroughfare. Police made some arrests, “people moved to the sidewalk and peace was restored,” Dotson said.

But when officers left, the protesters returned, marched on to Interstate 70, blocked it and returned to the intersection, he said.

Responding officers were struck with bricks and bottles, he added.

“At at that point, after the crowd ignored repeated requests and directions, inert smoke was used,” Dotson said. “After that didn’t have an effect, tear gas was used.”

He also said a car was set on fire, and some business burglarized.

“There’s a line that gets crossed from peacefully protesting, which we will support, to when laws are broken ,” Dotson said. “Police officers have to do their job.”

St. Louis Alderman Antonio French, who rose to fame during protests last year in Ferguson posted photos and videos of firefighters extinguishing house fires.

The tensions

Relations have been tense between police and some residents in St. Louis for some time now. The tension ratcheted up after Michael Brown, a black teenager, was shot and killed by a white officer in Ferguson, Missouri, a suburb of St. Louis, a little more than a year ago. His death sparked protests and reignited a national conversation around race and policing.

The two officers involved in Wednesday’s shooting have been placed on administrative leave, per police policy. An investigation is ongoing.

Dotson said the suspect’s gun was reported stolen. The second suspect who ran from the house remains on the loose.

Other individuals who had been in the house were taken into custody without incident, the chief said.

Officers recovered a total of four guns, including one inside the home, two that were tossed over a fence as the suspects were running and the weapon that the suspect had, according to Dotson. Three of the four were stolen, he said.