New York - From the White House to local communities, Americans are pushing for more police to wear body cameras after an officer shot dead an unarmed man running away from a traffic infraction.
The killing of Walter Scott, a 50-year-old black man, shot in the back by a white officer on Saturday in South Carolina and filmed on a cell phone, shocked America and shocked the world.
US officers are rarely indicted in shootings, but Michael Slager, 33, was charged with murder, sacked and faces up to life in prison or the death penalty if convicted at trial.
He initially claimed he felt threatened, but the emergence of the video so fundamentally contradicted his account that it has fueled calls for more widespread use of police body cameras.
The devices, which cost an estimated $1 000 compared to $5 000 for dashboard cameras, are still a new innovation in the United States but experts predict they could become standard equipment in the next three to five years.
‘Benefit of the doubt’
"In the past it was always the case that people gave the police the benefit of the doubt," said David Harris, a law professor at the University of Pittsburgh who studies police practices.
"That is beginning to change," he told AFP. "There is no doubt whatsoever that if that cell phone video had not surfaced that officer would be out on patrol in a police car right now."
A series of killings of unarmed black men by largely white police officers last year sparked nationwide protests, charges of racism and revived the debate about excessive use of police force.
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Harris says the killing of 18-year-old Michael Brown in Ferguson, Missouri in August, in bitterly disputed circumstances, and then millions of Americans strolling around with smart phones capable of filming video is changing attitudes towards body cameras.
Could reduce violence
"A few police departments were trying them out but it wasn't until this year that people began to really pay attention," said Harris.
Preliminary US studies and studies from Britain show that they are great at collecting evidence, fending off bogus complaints and - most often - back up officers accounts, said Harris.
One study from Rialto, California in 2012 found that for officers with cameras, complaints from the public dropped almost 90% and uses of force went down nearly 60%.
"If we issue them to all police, have reasonable rules, train for it and so forth we should see a diminishment of these kind of incidents," Harris told AFP.
The issue has harnessed political support from the top down.
White House spokesperson Josh Earnest said police body cameras "could have a positive impact in terms of build and trust between law enforcement officers and the communities they serve."
Marlon Kimpson, a South Carolina state senator who represents North Charleston, where Scott was killed, is pushing a bill that would force all law enforcement officers to wear body cameras.
In North Charleston - where blacks make up the largest population group and police are overwhelmingly white - mayor Keith Summey promised to speed up the introduction of police body cameras.
Pilot program in New York
While police departments already have cameras in patrol cars, headquarters and interrogation rooms, body cameras are still at pilot stage in various cities across the United States.
New York, the largest force in the country, began a pilot program only last December in five of precincts and one service area.
The move came six months after the death of father-of-six Eric Garner in a police chokehold that sparked nationwide protests.
Police enjoy significant legal leeway in the United States and prosecutors and civilian grand juries are often reluctant to indict them over excessive force.
Hugh Keefe, a Connecticut lawyer who has defended officers, warned some police who may already resent having to tape interviews would definitely resist the introduction of body cameras.
"I think if nothing else, they will make the cops more careful and better behaved," he told AFP.
But Harris warned body cameras were not the answer to all of America's problems between citizens and police.
"It's important to understand that by themselves they don't change the fundamentals of our system," he said.
"They don't change the law, they don't change the standard for using police force or using deadly force, they don't change the rules for grand juries."