WASHINGTON (AFP) - Two independent studies have for the first time laid bare how many civilians died at the hands of the United States police over the course of a year: about three a day.
The tallies, carried out by The Washington Post and the Guardian newspapers, are likely to fuel simmering outrage in many US communities that feel police officers are too quick to use deadly force.
America has in recent years been shaken by a series of fatal police shootings that have prompted calls for reforms of law enforcement tactics.
Some of the highest-profile incidents have involved white officers killing unarmed black men or youths, with many of the deaths caught on video camera.
The shootings have galvanized the Black Lives Matter national movement, which has helped raise awareness around the disproportionate rate at which unarmed black men are killed by police.
Because the Federal Bureau of Investigation (FBI) only tallies "justifiable homicides" of felons by police officers, and not the overall number killed, the US edition of the Guardian and the Post set about keeping their own counts.
The FBI's official tally of justifiable homicides in 2014 was 444 (2015 is not yet available.) The agency's national tally is also incomplete because reporting is voluntary, and not all police departments submit data.
US Attorney-General Loretta Lynch has announced plans to improve data collecting for use-of-force incidents involving police, calling it "vital for transparency and accountability".
According to The Counted, the Guardian's site, 1,130 people had as of Thursday been killed by the police in 2015 - more than three a day on average.
The Post, which only counted people killed by gunshot, put the number at 979.
The Post found most of those were either armed, had mental troubles or were fleeing officers who had told them to stop.
In the bulk of cases where officers killed an armed suspect, the individual was white, the newspaper notes, adding that 36 officers have been shot and killed in 2015.
However, when it comes to unarmed suspects, black men are disproportionately impacted.
The Post found that though black men make up only 6 per cent of the US population, they made up 40 per cent of the cases in which the police killed an unarmed man in 2015.
Yet another high-profile case unfolded last Saturday in Chicago, when police fatally shot Ms Bettie Jones, 55, a mother of five, and Mr Quintonio LeGrier, a 19-year-old engineering student.
Both died after the police came to a private residence in response to a domestic violence call.
The city's Mayor Rahm Emanuel said more police officers should be armed with Taser stun guns and given additional training.
"There's a difference between whether someone can use a gun and when they should use a gun," Mr Emanuel said, after cutting short his vacation and returning to the city.
The shootings come with Chicago's police already under federal investigation over a video that shows a white police officer, Jason Van Dyke, shooting a black teen 16 times, with most of the gunshots fired as the boy was lying motionless on the ground.
Van Dyke has pleaded not guilty to murder.
The shooting of 17-year old Laquan McDonald, which took place in 2014, has triggered a federal civil rights probe into the police and calls in some corners for the resignation of Mr Emanuel - a former top White House aide to President Barack Obama.
In the rare cases where the police are charged with wrongdoing in shootings, they are often cleared, as they only need to show they felt their lives were in danger at the time of the incident.
Because so many people in America have guns, officers are trained to assume every suspect could be armed.
In a recent study in the Public Library of Science (PLOS), researchers from Harvard University urged better national counting of police killings.
"Law-enforcement-related deaths, of both persons killed by law enforcement agents and also law enforcement agents killed in the line of duty, are a public health concern," the study notes.
