Police killings in the U.S., especially of black people, have sparked protests in cities across the country over the last year and a half.

Black Lives Matter, a loosely organized movement protesting violence against black communities by law enforcement and pushing for institutional police reforms, brought many stories of black people killed by police officers to the forefront in 2015.

One such case is the death of 12-year-old Tamir Rice, who was shot and killed by a police officer when Rice was seen with a replica handgun in Cleveland. A grand jury decided against indicting the officers involved earlier this week.

Here are updates to other similar stories that galvanized Black Lives Matter.

Laquan McDonald

In October 2014, Chicago Officer Jason Van Dyke confronted 17-year-old Laquan McDonald, who was wielding an eight-centimetre blade and suspected of breaking into vehicles. While McDonald was walking away from police Van Dyke shot him 16 times, expending the entire magazine of his 9-mm semi-automatic firearm.

Van Dyke told investigators he shot in self-defence after the teen aggressively approached him, but a police car dash-cam, which recorded the incident, seemed at odds with his version of events.

Fatal shooting of Laquan McDonald (edited version of graphic dashcam video)1:49

Chicago's police chief was fired after the release of the video earlier this year, and Mayor Rahm Emanuel was accused of covering up the video and delaying its release while he was running for re-election, which he won in April.

Van Dyke has been charged with first-degree murder and was out on bail pending a formal arraignment Dec. 29.

Walter Scott

In April, 50-year-old Walter Scott was shot dead by Officer Michael Slager after Scott was pulled over in North Charleston, N.C., regarding a broken brake light.

Slager initially claimed the shooting was in self-defence, but video recorded on a cellphone by witness Feidin Santana documented a different scenario. The footage showed Scott was about nine metres away from Slager when he was shot eight times while running away, with his back to the officer. It's been said Scott ran from police because he was behind on his alimony payments.

Police dashcam footage moments before shooting of Walter Scott4:02

After the video was made public, Slager was charged with murder and fired, and a judge ordered him jailed without bond. He was later indicted.

Protesters and advocates said the response from officials would have been different had the incident not been recorded by Santana. Mayor Keith Summey announced that he had ordered 15 more body cameras so that every uniformed officer on the street will wear one.

Freddie Gray

In April, 25-year-old Freddie Gray was arrested for possessing a switchblade knife outside a housing project in the west side of Baltimore.

Gray was handcuffed and shackled during a seven-block, 45-minute journey in the back of a police van, but he was not buckled in with a seatbelt.

freddie gray

Freddie Gray, 25, was arrested for possessing a switchblade knife outside a housing project on Baltimore's west side. Gray died a week later from a spinal cord injury he received while in police custody. (Murphy, Falcon & Murphy)

Officers found Gray after the journey with a broken neck and a severe spinal injury. He was sent to hospital and died one week later.

An autopsy concluded Gray was unable to brace himself when the van was turned or braked suddenly, and prosecutors argued Gray would still be alive if officers had buckled him in.

Officer William Porter, the first of six officers indicted, was charged with manslaughter, assault, misconduct in office and reckless endangerment in Gray's death, but his trial ended in a hung jury.

Quintonio LeGrier and Bettie Jones

In December, Chicago police responded to an early-morning domestic disturbance call.

A statement by the Chicago Police Department said officers arrived at the home and "were confronted by a combative subject resulting in the discharge of the officer's weapon."


Family members tape up a picture of Bettie Jones while participating in a vigil outside where Chicago police shot and killed her. (Tannen Maury/EPA)

The subject of the call, 19-year-old Quintonio LeGrier, and his neighbour Bettie Jones, 55, were both shot dead, LeGrier was shot 11 times and Jones three times.

Chicago police said Jones was accidentally shot when she opened her door for police, and the officers involved will be placed on administrative duties for 30 days while the incident is under review.

Sandra Bland

In July, 28-year-old Sandra Bland was pulled over in Dallas for failing to signal a lane change while on her way to a job interview.

Woman Dead In Jail

A traffic stop in Texas escalated into the arrest of Sandra Bland and, ultimately, her death behind bars. (Bland family via Associated Press)

The traffic stop became confrontational when Texas Trooper Brian Encinia pointed a stun gun at Bland when she wouldn't exit her car.

Bland was arrested for assault of a public servant and placed in jail, where officers found her dead in her cell three days later, hanging from a noose made from a plastic liner taken from a trash can.  

Bland's family has criticized the stop and her incarceration.

The FBI is looking into the incident. Dallas police are conducting an internal review of the traffic stop and have put Encinia on administrative duty.

With files from The Associated Press and Reuters