JOHANNESBURG — His hands are tied to the rear of a police van while his body lies behind it, on the ground. The van speeds off, dragging the slender man along the pavement as a onlookers shout in dismay and at least one records the scene. He is later found dead in a police cell.

It's a gut-wrenching video, made all the more disturbing by the fact that the men who carried out the abuse were uniformed South African police officers and the van was a marked police vehicle. The Daily Sun, a South African newspaper, posted the footage Thursday, and it was quickly picked up by other South African news outlets and carried on the Internet. It sparked immediate outrage.

Some of those in the crowd who watched the scene unfold in a township east of Johannesburg shouted at the police and warned that it was being videotaped. The police did not seem at all concerned as they tied Mido Macia, a 27-year-old taxi driver from neighboring Mozambique, to the back of a police vehicle, his hands behind his head, his buttocks on the ground. At least three policemen participated in the incident. Macia was found dead in a police cell late Tuesday in the Daveyton township east of Johannesburg.

The Independent Police Investigative Directorate, the police watchdog agency, said Thursday that a murder probe is under way and that Macia suffered head and other injuries, including internal bleeding.

'What has this guy done?'
The graphic footage renewed concerns about brutality, corruption and other misconduct by a national police force whose reputation has suffered in recent years amid reports that many officers lack training. Some have been charged with committing the crimes they are supposed to prevent, including rape and murder.

"We are going to film this," several onlookers shouted in Zulu as the police tormented Macia. One bystander can be heard on the videotape shouting in Zulu: "What has this guy done?"

Daily Sun via AFP - Getty Images

South African police officers hold the legs of a taxi driver handcuffed to the back of a police van. Moments later, they dropped his legs and the van accelerated away. He was later found dead.

At first, Macia, dressed in jeans and a red T-shirt, is dragged along the road by the vehicle at slow speed, the footage shows. He awkwardly tries to keep step even though he is almost horizontal above the ground. Then the van stops, two policemen pick up the legs of the taxi driver and drop them to the ground as the van picks up speed and drives off, beyond the view of the camera.

The police watchdog agency said the incident started just before 7 p.m. on Tuesday when the cab driver was allegedly obstructing traffic with his vehicle. Then, Macia allegedly assaulted a constable and took his weapon before he was overpowered, the Independent Police Investigative Directorate said in a statement.

Macia was found dead over two hours later by another policeman, according to the watchdog agency.

In a statement, the police force said National Police Commissioner Riah Phiyega "strongly condemned" what happened. The statement said people are "urged to remain vigilant and continue to report all acts of crime irrespective of who is involved."

Phiyega has sought to upgrade the reputation of the South African police. Last month, Phiyega told a group of police officials the standing of the force "has been severely but not irreparably tarnished over the past several years."

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