Protestors and police clash in St Louis after cop acquitted of murdering a black man

8 police officers were injured in clashes with demonstrators in St Louis when a relatively peaceful protest turned violent.

The clashes erupted after a Missouri judge acquitted a former police officer of murder in the 2011 fatal shooting of a black man suspected of drug dealing.

After most protestors drifted away, a smaller group of policemen, described as “agitators” by resident, lingered on in the streets of the upscale neighbourhood near the mayor’s home.

Police resorted to tear gas and rubber bullets to control the crowd as vandals broke windows at a library, a restaurant and a home.

Protestors also threw bricks and water bottles at the officers.

Police reported making at least 13 arrests and taking three officers to hospital.

“Reports of bricks thrown at police. That’s not protest. That’s a crime. We stand behind our officers. This violence won’t be tolerated,” Missouri Governor Eric Greitens said on Twitter.

Authorities urged clam during the aftermath as comparisons to the Ferguson protest that gave rise to the Black Lives Matter movement in 2014 were drawn.

The outcry was prompted by Friday’s verdict, where former city policeman Jason Stockley, 36, was found not guilty of first-degree murder in the shooting death of Anthony Lamar Smith, 24.

Smith was shot 5 times in his car after trying to escape from Stockley and his partner who were following him on an alleged drug deal.

During the pursuit, Stockley could be heard saying on an internal police car video he was going to kill Smith, prosecutors said.

At Stockley’s direction, his partner, who was driving, slammed the police cruiser into Smith’s vehicle and they came to a stop, court documents said. Stockley then approached Smith’s car and opened fire with his service weapon.

The former policeman believed Smith was armed, defense attorneys said, and a gun was found in the car. But prosecutors argued Stockley planted the weapon and that the gun had only Stockley’s DNA on it.