People gather for the national Justice For All march against police violence in Washington DC
People gather for the national Justice For All march against police violence in Washington DCReuters

Police departments in the US are implementing a change in procedure to alleviate public distrust after protests over the killings of black people.

The use of deadly force is one of the policies looked into as well as protecting officers from retaliation.

The NYPD plans to issue stun guns to hundreds more officers and also to equip some with body-mounted cameras to record interactions with the public.

Milwaukee police are participating in mandatory crisis-intervention training, while in Akron Ohio, officers on the beat have started working in pairs on every shift, according to Sky News.

In Philadelphia, Mayor Michael Nutter cautioned police in a video message to use force only "if absolutely necessary."

These actions have been instigated by a groundswell of anger from people who have been demonstrating in their thousands at the actions of police officers which have resulted in the deaths of black men.

"It's not a mistake or a coincidence that a lot of these departments are publicising their training or are perhaps revamping their training guidelines and things like that in the wake of these really high-profile incidents," said Kami Chavis Simmons, director of the criminal justice programme at the Wake Forest University School of Law.

Lorie Fridell, a criminology professor at the University of South Florida who operates a police training business, says she has received nearly two requests a day from police chiefs since August.

"There's a lot of well-meaning chiefs out there that want to do the right thing, and they are looking for ways that they can address not just use-of-force issues but bias issues," she said.

Ohio Attorney General Mike DeWine asked the state's police training commission last week to study possible updates in the way officers learn their jobs.

"Every police officer who goes out every day has the right to come home at night," DeWine told KXNews. "On the other hand, citizens of the state of Ohio have the right to expect that police officers are correctly trained and vetted before they're put out on the street."

Civil rights organisers have also called for legislation that would allow federal prosecutors to take over cases involving police.