George Floyd's death sparked heated protests across US as many call for charges against officers - CNN

Three others were also at the scene.

Who the four officers are

The four officers involved in the man's death have been fired from the Minneapolis Police Department.

The mayor of Minneapolis also called for charges against the officer who kept his knee on Floyd as the man begged for help.

"For five straight minutes a white officer on our police department pressed his knee into the neck of a black man who was handcuffed, who was no threat and was articulating very clearly how he was impacted, how his physical health was being damaged and how he couldn't breathe," Mayor Jacob Frey told CNN Wednesday night.

Please."

Williams said he tried to approach an officer and ask what was happening because he noticed Floyd's nose was bleeding and his "eyes just turning a different color."

But the officers didn't give an explanation as to why one police officer's knee remained on Floyd's neck and instead told Williams Floyd was "resisting arrest."

"I said 'officer, he's not resisting arrest, you have your knee on him and you have handcuffs on him, he's detained at this moment,'" he said.

A medics team that responded to the incident worked on an "unresponsive, pulseless male," according to a Minneapolis Fire Department narrative released by police.

He does not appear to be resisting arrest.

Bodycam footage was also released by the Minneapolis Park Police -- a separate entity from Minneapolis police -- which is heavily redacted.

The officer from the Minneapolis Park Police responded to the scene and assisted the Minneapolis Police Department but the officer was not facing the direction where the incident with Floyd occurred.

In a statement, the Minneapolis Park Police said the officer was about 118 feet away from where Floyd was pinned to the ground and not in a position to intervene.