FILE - This undated file photo provided by the St. Louis Police Department shows former St. Louis police officer Jason Stockley, who is charged with first-degree murder and armed criminal action in the December 2011 shooting death of Anthony Lamar Smith. A television station reported that a ruling is expected Friday, Sept. 15, 2017, in Stockley's case, and Missouri Gov. Eric Greitens has put the National Guard on standby in case unrest breaks out. (St. Louis Police Department via AP, File)

ST. LOUIS - A judge acquitted a white former St. Louis police officer of murder in the 2011 killing of a black drug suspect, sparking street demonstrations that put protesters face-to-face with police in riot gear.

Judge Timothy Wilson found the former officer, Jason Stockley, not guilty of first-degree murder in the fatal shooting of 24-year-old Anthony Lamar Smith. The bench ruling Friday came more than a month after testimony concluded.

Activists had threatened civil disobedience if Stockley was acquitted, and authorities took steps to deal with that scenario. All three downtown courthouses, including the federal courthouse, and some city schools were closed on Friday in anticipation of the verdict.

The police department said officers would be working 12-hour shifts starting Friday and Mayor Lyda Krewson said the State Highway Patrol and St. Louis County police would provide support, with the patrol handling any protests on state highways.

Republican Gov. Eric Greitens, meanwhile, put the National Guard on standby in case of unrest. He and the mayor urged protesters to be peaceful, a sentiment echoed by Smith's fiancée, Christina Wilson.

Here's a look at the case:

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THE SHOOTING

Stockley and his partner saw what appeared to be a drug transaction in the parking lot of a fast-food restaurant on Dec. 20, 2011. As the officers sought to corner Smith, he drove away. Stockley's defence attorney, Neil Bruntrager, said the officers were nearly run over. Stockley fired at the fleeing car, then a car chase began.

Police dashcam video captured Stockley saying, "going to kill this (expletive), don't you know it," in the midst of the chase. As Smith's car slowed, Stockley told his partner to slam the police SUV into it, and his partner did so. Stockley then got out of the SUV and fired five shots into Smith's car, killing him.

Bruntrager said Stockley fired only after Smith refused commands to put up his hands and reached along the seat toward an area where a gun was found. But prosecutors said Stockley planted the gun. Testing found Stockley's DNA on the gun, but not Smith's.

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DIFFERENT PASTS

Stockley, now 36, graduated from a Catholic high school in nearby Belleville, Illinois, then went to the U.S. Military Academy at West Point. After graduation, he served in Iraq, where he was injured and awarded the Army Bronze Star. Stockley joined the St. Louis Police Department in 2007. He resigned in 2013, about two years after the shooting, and moved to Houston.

Smith had a 1-year-old daughter when he died. His family has not disclosed much about him. Court records show he had a criminal record that included convictions for unlawful possession of a firearm and drug distribution. At the time of the shooting, he was on probation for a theft charge related to a 2010 crime in the St. Louis suburb of Ferguson. In 2013, the St. Louis Board of Police Commissioners reached a $900,000 settlement with Smith's family, ending a wrongful-death lawsuit filed on behalf of Smith's daughter.

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NEW EVIDENCE

The circuit attorney's office initially decided not to charge Stockley, but police internal affairs brought new evidence in March 2016. Then-Circuit Attorney Jennifer Joyce announced in May 2016 that Stockley was charged with first-degree murder.

The new evidence wasn't disclosed, but the St. Louis Post-Dispatch obtained the dashboard camera video and published it soon after charges were announced. The footage outraged activists.

Prosecutors opted not to pursue the death penalty. Stockley chose to have the case decided by a judge, rather than a jury, and the judge agreed despite the objections of prosecutors.

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RACIALLY CHARGED ISSUE

Police and courts in the St. Louis area have been under scrutiny since the 2014 fatal shooting by police of 18-year-old Michael Brown in Ferguson. Brown, who was black and unarmed, was fatally shot by a white officer after they skirmished in a street. Weeks of often-violent protests followed, and violence was renewed that November after a grand jury declined to indict the officer, who resigned that month.

Since then, police have fatally shot several other black suspects in St. Louis. Stockley is the only St. Louis police officer to be charged with murder in recent years.

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