Waseem Abbasi

USA TODAY

In a case that reignites the debate over a lack of convictions of officers in police shootings, particularly involving African Americans, a white former St. Louis police officer was acquitted of murder Friday in the deadly shooting of a black man.

Circuit Judge Timothy Wilson found Jason Stockley not guilty on charges of first-degree murder and armed criminal action. Stockley was charged more than four years after the 2011 shooting death of Anthony Lamar Smith. His acquittal sparked violent protests in St. Louis on Friday evening.

Despite viral videos and widespread concern over fatal shootings of unarmed black men in the United States, convictions of cops have been rare — even in high-profile cases.

According to a research study by professor Philip Stinson of Bowling Green State University in Ohio, there are around 1,000 police shootings each year in the U.S. Since 2005, when Stinson started keeping record of the shootings, about 35% of the officers were convicted for fatal on-duty shootings. The rest were either pending trial or not convicted.

Here are some of the high-profile cases:

Convicted

Peter Liang

Case summary: In the fatal shooting of Akai Gurley, 28, at a New York housing project, police officer Peter Liang claimed it was an accidental discharge. Liang, who had been on the job for 18 months, was on patrol in a dark stairwell of the building in November 2014 when he fired his gun. The bullet deflected off a wall and struck the victim in the chest.

Outcome: Liang, who was immediately fired from the New York Police Department, was found guilty of manslaughter and official misconduct on Feb. 11, 2016, but supporters claim the officer was singled out for prosecution as a Chinese-American. A judge later reduced the jury's conviction to criminally negligent homicide and sentenced Liang to five years probation and 800 hours of community service.

Not Charged

Daniel Pantaleo

Case summary: In this internationally known case, Eric Garner, a 43-year-old black man, died after being tackled to the ground and held in a chokehold by New York police officers for allegedly selling cigarettes illegally. Garner, who has asthma, said "I can't breathe" as the incident was captured on cellphone video. He died later that day on July 17, 2014.

Outcome:A grand jury decided not to indict officer Daniel Pantaleo in December 2014 and the city settled with Garner's estate for $5.9 million. Pantaleo was placed on modified duty at the New York Police Department after Garner's death.

Darren Wilson

Case Summary:On Aug. 9, 2014, unarmed 18-year-old Michael Brown was fatally shot by police officer Darren Wilson after a struggle in Ferguson, Mo. He was shot 12 times.

Outcome: A grand jury decided not to indict Wilson on Nov. 24, 2014, sparking angry protests. After a grand jury cleared Wilson, he wanted to rejoin Ferguson’s police force but was told that might put other officers at risk.

Timothy Loehmann

Case Summary:In November 2014, 12-year-old Tamir Rice of Cleveland was shot by a police officer while carrying an air pistol. The officer, Timothy Loehmann, was responding to a 911 call claiming a person was pointing "a pistol" at people. Loehmann, an officer in training, shot Rice within moments of arriving at the scene.

Outcome: A grand jury decided not to indict Loehmann and another officer, Frank Garmback, on Dec. 28, 2015. Administrative charges have been filed against three officers this year. Loehmann was fired by the city of Cleveland in May. The city cited alleged misinformation on his employment application to the Police Department, not his conduct in the shooting.

Blane Salamoni and Howie Lake II

Case summary: In July 2016, a 37-year-old Louisiana man, Alton Sterling, was fatally shot after being pinned to the ground by officers outside a Baton Rouge convenience store. Police said he was reaching for a gun.

Outcome: Federal prosecutors announced in May that there isn't enough evidence to warrant civil rights charges against officers Blane Salamoni and Howie Lake II. State charges are possible. They are on paid leave from the police department.

Acquitted/ Charges dropped

Caesar Goodson Jr., Brian W. Rice, William Porter, Alicia D. White, Garrett E. Miller, Edward M. Nero

Case summary: In April 2015, Freddie Gray, 25, was arrested by Baltimore police after he was found with a knife in his pocket. Gray died after suffering a neck injury while in police custody. On May 21, 2015, a Baltimore grand jury indicted six police officers on charges including involuntary manslaughter and reckless endangerment.

Outcome: Three were found not guilty by Judge Barry Williams, the other three had their charges dropped on July 27. The Gray family and the city of Baltimore reached a $6.4 million civil settlement in September.

Betty Jo Shelby

Case summary: Betty Jo Shelby, 43, says she was driving to another police call on Sept. 16 when she came upon Terence Crutcher, standing alongside the road. She said she then saw an SUV straddling the center line with its engine running and doors open. Graphic videos show Crutcher, 40, walking toward his SUV with his hands up and his back to multiple officers. Crutcher appears to place his hands on his vehicle when he falls to the ground, shocked with a stun gun fired by one officer and shot by Shelby.

Outcome: Shelby was acquitted on May 17 of a first-degree manslaughter charge. The police department reinstated her after the verdict, putting her back on the force.

Mistrial

Michael Slager

Case summary: In another incident in April 2015, 50-year-old Walter Scott, driving with a broken brake light, was shot while running from North Charleston police officer Michael Slager. The officer, who was fired from the police force, was charged with first-degree murder after a cellphone video was released.

Outcome:A mistrial was declared in 2016. Last month, Slager pleaded guilty to a federal charge of using excessive force. State murder charges against Slager were dismissed as part of the plea deal.

Ray Tensing

Case summary: In July 2015, Samuel DuBose was pulled over for a missing front license plate and shot in the head. The incident was captured on body camera video. The officer, Ray Tensing, was charged with murder and voluntary manslaughter. Tensing testified that he was being dragged by the left arm when he reached up and shot DuBose, while prosecutors said he wasn't being pulled by the car and didn't need to fire at DuBose.

Outcome: Mistrial declared in 2016. A retrial resulted in another mistrial in June. Tensing was fired from the police force.

Cases that haven't gone to trial yet

Jason Van Dyke

Case summary: A 17-year-old teenager, Laquan McDonald, was shot 16 times by a police officer in October 2014. Contrary to police claims that McDonald lunged toward officers, the dash cam video showed McDonald walking away from police as he held a 4-inch knife at the time of his death.

Outcome: The officer, Jason Van Dyke, was charged with first-degree murder and indicted on 16 additional counts of aggravated battery in March this year. He has pleaded not guilty. The new grand jury indictment brings to 23 the number of felony charges against Dyke, previously charged with six counts of first-degree murder and one count of official misconduct.

In August, Superintendent Eddie Johnson recommended Van Dyke and other officers involved in the shooting be fired. Van Dyke was suspended without pay and has been working as a janitor, according to the Chicago Tribune.

Roy Oliver

Case summary: Unarmed black teenager Jordan Edwards, 14, was fatally shot by a Texas police officer as he was riding in a car while leaving a house party on April 29. Edwards was in the front passenger seat when an officer fired into the car.

Outcome: Officer Roy Oliver was fired and prosecutors charged him with first degree murder in May. He turned himself in and remains free on bond.

Ashley May contributed to this report.