Story highlights
The Michael Brown case didn't yield criminal charges, but the Justice Department sued the city of Ferguson
The killing of Walter Scott led to South Carolina mandating the use of police body cameras
The protests happen with such frequency, the images seem like deja vu: Demonstrators flooding city streets, demanding an end to excessive police force and chanting “black lives matter.”
But each case that spurs “black lives matter” marches has different circumstances – and different outcomes. Here are how some high-profile cases have turned out:
Trayvon Martin, 17

Date of death: February 26, 2012
Where: Sanford, Florida
What happened: Martin was walking from a convenience store back to the home of his father’s fiancee. Neighborhood watch volunteer George Zimmerman spots him from his car and calls 911, reporting “a real suspicious guy.”
“This guy looks like he’s up to no good, or he’s on drugs or something,” Zimmerman told a dispatcher. “It’s raining, and he’s just walking around.”
A scuffle broke out, but there were no direct witnesses. Zimmerman claimed Martin attacked him, hitting him in the nose and knocking him onto the pavement. Zimmerman said he then took out his gun and shot Martin in self defense.
But critics said Zimmerman was unjustified in confronting the unarmed teen, especially since Zimmerman didn’t heed a police dispatcher’s advice to stop following him.
The outcomes: Zimmerman was charged with second-degree murder but was found not guilty. The acquittal ignited protests across the country, and the “Black Lives Matter” movement gained national prominence.
The case also led to the firing of Sanford Police Chief Bill Lee, who was criticized for not arresting Zimmerman after Martin was killed.
Why this verdict? Five things that led to Zimmerman’s acquittal
Eric Garner, 43

Date of death: July 17, 2014
Where: New York City
What happened: Police tried to arrest Garner in front of a store for allegedly selling cigarettes illegally. Garner raised both hands and told officers not to touch him. Seconds later, Officer Daniel Pantaleo grabbed the 350-pound man in a chokehold and pulled him to the sidewalk, rolling him onto his stomach.
The New York Police Department prohibits the use of chokeholds.
Garner, who had asthma, repeatedly said, “I can’t breathe! I can’t breathe!” while several officers restrained him on the ground. Police said he suffered a heart attack and died en route to a hospital.
The outcomes: A grand jury declined to indict Pantaleo, sparking protests and “die-ins.”
Garner’s death also spurred a new protest slogan: “I can’t breathe,” referring to some of his final words before he died. Several professional athletes wore shirts saying “I can’t breathe” in silent protest.
Pantaleo offered his condolences to Garner’s family and said he never intended to hurt Garner. The police union defended Pantaleo, saying he just wanted to take Garner into custody after the suspect resisted.
New York City eventually settled with Garner’s family for $5.9 million. City Comptroller Scott Stringer said the settlement “acknowledges the tragic nature of Mr. Garner’s death,” but “the city has not admitted liability.”
Michael Brown, 18

Date of death: August 9, 2014
Where: Ferguson, Missouri
What happened: Brown was walking with a friend in the middle of a street when Ferguson Police Officer Darren Wilson approached them and told them to walk on the sidewalk.
After that, the narratives varied enormously. Authorities said Brown had attacked the officer in his car and tried to take his gun. Others said the teenager was surrendering, his hands in the air to show he was unarmed, when the officer opened fire. Documents showed that Wilson fired his gun 12 times.
What happened when Michael Brown met Officer Darren Wilson
The outcomes: A grand jury decided not to indict Wilson – leading to heated and sometimes violent protests in Ferguson and across the country.