Fatal shootings by police are growing, a newspaper’s investigation clearly shows.

As the use of deadly force by police again roils the US, the number of fatal shootings by officers has increased from 465 in the first six months of last year to 491 for the same period this year, according to an ongoing two-year study by the Washington Post.

This year has also seen more officers shot and killed in the line of duty and more officers prosecuted for questionable shootings.

Two years after a white police officer shot and killed a black teenager in Ferguson, Missouri, the pace of fatal shootings has risen slightly while the grim encounters are increasingly being captured on video and stoking outrage.

On Wednesday NZT, two white police officers in Baton Rouge, Louisiana, shot and killed a black man whom they had pinned to the ground outside a convenience store.

A black man is fatally shot by police during a traffic stop in Minnesota

The event was captured in a video that went viral online, and within hours the US Department of Justice launched a civil rights investigation.

On Thursday, an officer in Falcon Heights, Minnesota, fatally shot a black man during a traffic stop. Video of the shooting a has received widespread attention.

"I feel change is not coming," said Porsche McCullough, whose 29-year-old black female cousin was shot and killed by an Asian San Francisco police officer in May.

"The community is tired. They are tired of seeing black people shot, poor people shot, people with substance-abuse problems shot."

A Washington Post database that tracks fatal shootings by police shows a 6 per cent increase in the number of such deaths during the first six months of 2016 compared with the same period last year. Details of the fatal encounters so far this year remain strikingly similar to shootings in all of 2015: Blacks continued to be shot at 2.5 times the rate of whites.

About half of those killed were white and about half were minorities. Fewer than 10 per cent of all those killed were unarmed. One-quarter were mentally ill.

But there are notable differences: More of the shootings were captured on video, from 76 to 105 in the first half of each year. And the number of fatal shootings of black women, such as Nelson-Williams, has risenfrom eight so far this year compared with 10 in 2015.

Last year, the Washington Post began to log every fatal police shooting in the US and then analysed more than a dozen details about each event. The project revealed that in 2015, nearly 1000 people were fatally shot by police, more than twice the average annual number reported by the FBI in previous years.

The Post has expanded the effort in 2016, culling media reports and filing hundreds of public-records requests to obtain the names and work histories of officers involved in fatal shootings.

As in 2015, in most fatal shootings this year officers were confronted by subjects armed with guns.

In half of these cases, they fired at police, prompting officers to fire to defend themselves or to protect bystanders. In the first six months of this year, 20 officers were fatally shot in the line of duty, compared with 16 in the first six months of 2015, according to the Officer Down Memorial Page.

Officials representing rank-and-file officers say it is criminals who make it hard to reduce the number of fatal shootings by police.

"Police are dealing with a lot of violent individuals," said Jim Pasco, executive director of the Nashville-based national Fraternal Order of Police. "And the criteria for using deadly force hasn't changed essentially, so why would the numbers change?"

After Ferguson, pleas for reforms focused on reducing certain types of shootings, such as those of individuals who are unarmed or experiencing mental-health crises as opposed to violent criminals who initiate shootouts with officers.

A White House task force called for teaching officers new skills to de-escalate volatile encounters. Hundreds of police chiefs also pushed new policies for dealing with the mentally ill. And thousands of departments began outfitting officers with body-cameras, hoping this would curb the use of excessive force.

The FBI also vowed to improve its data collection on the fatal use of force by police. The agency said in January 2017, it would start to compile a more accurate tally and collect dozens of details about the incidents in order to analyse the events.

Family members and protesters march following the shooting death by police of Philando Castile. Photo / AP
Family members and protesters march following the shooting death by police of Philando Castile. Photo / AP

But widespread compliance with the FBI's initiative by police associations and departments isn't expected until 2019. The agency is seeking unanimous consent from numerous police groups regarding what data should be collected, a process that is still underway. And thousands of departments will need to build the software that will allow them to properly track and report the data. Even then, reporting will not be mandatory.

Training reforms, which the White House and police chiefs have embraced, also are rolling out in a slow, scattershot fashion. There are about 18,000 police departments in the US, many with their own training academies and unions.

There will be a "lag time"before there is a measurable drop in deaths, even among the departments that are earnestly embracing reforms, said James Alan Fox, a criminologist at Northeastern University in Boston.

"It takes time to get everyone through training," Fox said. "It takes time to change a culture."

In San Francisco, Porsche McCullough's cousin, Jessica Nelson-Williams, died on a foggy May morning as she tried to flee from police down a dead-end street driving a stolen Honda Accord. Sergeant Justin Erb fired a single shot into the car, striking Williams, killing her.

It was the third fatal shooting by police over the past seven months in the city. All of the dead were homeless; all of them minorities.

The local protests have rarely led to the nationwide demonstrations that turned past police shooting victims such as Brown, Tamir Rice in Cleveland, and Walter Scott in North Charleston, South Carolina, into household names.

"Are we becoming anaesthetised to these violent events? Are they happening so often we no longer feel moved?" said Cedric Alexander, a police chief in DeKalb County, Georgia, and member of the White House Task Force on 21st Century Policing.

Emmanuel Wint speaks to marchers to protest the shooting deaths of Philando Castile and Alton Sterlin. Photo / AP
Emmanuel Wint speaks to marchers to protest the shooting deaths of Philando Castile and Alton Sterlin. Photo / AP

This week's fatal shootings by police of Alton Sterling in Louisiana and Philando Castile in Minnesota have reignited the national outrage. How long it lasts remain to be seen.

In 2016, fatal shootings by police are increasingly captured by cameras, a Post analysis shows. In the first six months, at least 105 shootings have been recorded in whole or in part by police-body cameras, surveillance cameras, cameras mounted on patrol cars or bystanders' smartphone cameras. At this point last year, that number was 76.

The biggest shift has been in the use of body-cameras: 63 of the shootings have been captured through June, compared with 34 for the same period in 2015.

The videos have been a linchpin for prosecutors, activists and city mayors who want to hold police chiefs and officers accountable for questionable shootings.

Graphic video of fatal shootings has led to the firing of several police leaders, including Chicago Police Superintendent Garry McCarthy in December. On May 19, Police Chief Greg Suhr stepped down at the urging of the city's mayor, Ed Lee, hours after Nelson-Williams was killed in San Francisco. Although the killing was not captured on video, San Francisco police were recorded in the preceding months fatally shooting two homeless men.

In the past 18 months, murder and manslaughter charges brought against officers in fatal shootings have tripled, while the presence of video evidence in these cases has doubled.

From 2005 to 2014, 47 officers were criminally charged in fatal shootings, with 15 of those cases involving video evidence.

Family and friends of Alton Sterling protest on the corner of Fairfields Ave. Photo / AP
Family and friends of Alton Sterling protest on the corner of Fairfields Ave. Photo / AP

In 2015, 18 officers were criminally charged, with 10 of the cases involving video. And, so far this year, seven officers have been criminally charged, with five involving video evidence.

"With video, it no longer comes down to the word of police against people who are dead or against people who could be easily discredited," said Philip Stinson, a criminologist at Bowling Green State University in Ohio who studies arrests of police.

In Mesa, Arizona, prosecutors said they charged an officer after video contradicted his account of what led him to shoot and kill an unarmed man at a hotel.

On January 18, Officer Philip Mitchell Brailsford of the Mesa police responded to an emergency call from a La Quinta Inn where guests spotted someone pointing a rifle out of a fifth-floor window. Police traced the incident to a room where 26-year-old Daniel Shaver was drinking rum shots with a woman. When officers arrived, they ordered the two of them into the hallway.

Brailsford later told investigators that Shaver became unco-operative, made a "furtive movement"toward the waistband of his shorts, and that he feared Shaver was attempting to retrieve a gun. Brailsford shot Shaver five times. Brailsford is white and so was Shaver.

But Shaver was unarmed when shot, and the woman told a story that was different from the officer's. She said that seconds before being shot, Shaver was crawling towards officers, crying and saying, "Please don't shoot me."

Prosecutors said video from Shaver's body camera supported the woman's version of events. "Shaver was audibly sobbing as he crawled"towards officers, a police report said, adding that Shaver said, "No, please don't shoot me."

Brailsford was carrying an AR-15 rifle, with the phrase "You're F***ed"etched into the weapon. The police report also said the "shots were fired so rapidly that in watching the video at regular speed, one cannot count them".

The video also showed Shaver's shorts were falling off as he crawled, and, according to the police report, he may have reached toward his waistband to pull them up. Brailsford shot just as Shaver's empty hand moved back in front of him towards the ground, the report said.

Jamie Davis protest the shooting this week in Baton Rouge of Alton Sterling. Photo / AP
Jamie Davis protest the shooting this week in Baton Rouge of Alton Sterling. Photo / AP

Seven weeks later, Maricopa County Attorney Bill Montgomery filed a felony second-degree murder charge against Brailsford. During a private meeting with Shaver's widow, he said, "Your husband didn't do anything wrong. He didn't. He was trying to comply," according to an audio recording made by Shaver's widow and posted online.

Brailsford was fired by the department on March 21. His case is expected to go to trial next year.

Brailsford's lawyer, Mike Piccarreta, told the Post he thinks the body camera footage will clear his client. "It demonstrates that the officer had to make a split-second decision when [Shaver] moved his hands toward the small of his back after being advised that if he did, he'd be shot."

After her son's death on August 9, 2014, Michael Brown's mother began pushing for all police departments to equip their officers with body cameras. She has said the cameras may provide answers to grieving families, such as hers, when there are conflicting eyewitness accounts.

Civil rights groups and police associations that also support police use of the technology think the presence of video will change how officers respond and will drive down the number of police shootings.

FBI Director James Comey said as recently as May that he believes a "viral video effect"has changed officers' behaviour, making them wary of confronting suspected lawbreakers.

However, the Post's analysis suggests that the ubiquitous nature of video has not yet had the deterrent effect that police and civil rights groups have predicted - at least as it applies to fatal force.

10 cases of police killings

1. Gregory Gunn

Montgomery, Alabama, police officer Aaron Smith, who is white, has been charged with murder in the February shooting death of 58-year-old Gregory Gunn. Gunn was unarmed and steps from his home when he was shot in the early hours of February 25, according to police.

2. Akiel Denkins

A North Carolina prosecutor concluded that a white officer acted in self-defence when he shot a black man he was trying to arrest in Raleigh. Police have said 24-year-old Akiel Denkins pulled out a gun and reached for Officer D.C. Twiddy's weapon before the officer shot and killed him in late February.

3. Freddie Gray

Six Baltimore police officers faced charges ranging from misconduct to second-degree murder in the death last April of Freddie Gray. Gray, who was 25 and black, died when his neck was broken in the back of a police van. He had been restrained with handcuffs and leg irons, but not a seat belt. The death set off riots in Baltimore. The involuntary manslaughter trial of the first of those charged, Officer William Porter, ended in December in a hung jury. A judge acquitted two other officers in bench trials.

4. Walter Scott

Michael Slager faces up to 30 years in prison if convicted of murder in the death of Walter Scott, who was shot and killed fleeing a traffic stop in South Carolina in April 2015. Scott was unarmed. Slager, 34, who is white, was fired by the North Charleston Police Department and stands trial in October.

5. Laquan McDonald

Chicago Police Officer Jason Van Dyke is charged with first-degree murder in the 2014 death of black teen Laquan McDonald. An explosive dash cam video showed McDonald being shot 16 times. Van Dyke has pleaded not guilty and is free on bond.

6. Samuel Dubose

Ray Tensing, a former University of Cincinnati police officer, is awaiting an October trial on murder and voluntary manslaughter charges in the fatal shooting of Samuel DuBose, 43, who was unarmed when he was pulled over for a missing licence plate. Tensing, who is white, is free on bail. DuBose was black.

7. Akai Gurley

Peter Liang, a rookie New York City police officer of Chinese descent, was patrolling a public housing high-rise with his gun drawn in 2014 when he fired and a bullet ricocheted off a wall, hitting 28-year-old Akai Gurley, who was black. In April, a judge reduced the initial manslaughter conviction to negligent homicide and sentenced Liang to five years' probation and 800 hours of community service.

8. Jamar Clark

The November 15 shooting death of 24-year-old Jamar Clark sparked weeks of protests in Minneapolis. Officers Mark Ringgenberg and Dustin Schwarze were trying to arrest Clark when he was shot once in the head. He died a day later.

9. Brendon Glenn

Los Angeles Police Chief Charlie Beck in January recommended criminal charges be brought against Officer Clifford Proctor, who fatally shot an unarmed black man, 29-year-old Brendon Glenn, in the back. Investigators concluded Glenn was on his stomach trying to push himself up when he was shot.

10. Christian Taylor

An unarmed black university football player was shot and killed during a suspected burglary at an Arlington car dealership last August. Christian Taylor, 19, was shot after police officer Brad Miller, who is white, was called to the dealership. Miller was fired from the department. A grand jury decided to take no action against the officer. An autopsy determined Taylor likely used a synthetic psychedelic drug and marijuana before the incident.