Eight South African police officers involved in the death of a cab driver who was dragged behind a police vehicle have been arrested and charged with murder on Friday.

Gen. Riah Phiyega said Friday that she shares "the extreme shock and outrage" over a video showing the abuse of the Mozambican immigrant by police officers.

Phiyega said she fully supports the investigation by the police watchdog agency and added the rights of Mido Macia, a 27-year-old from neighbouring Mozambique, were "violated in the most extreme form."

The scandal is only the latest to undermine confidence in South Africa's police force.

In the video, broadcast around the world, police officers bind Macia's hands to the rear of a marked police van and speed off, dragging him through the streets as crowds look, shouting their dismay. The event reportedly took place around 7 p.m., and Micay was found dead in a police cell a few hours later on Tuesday night.

The graphic scenes of the victim struggling for his life shocked a nation long accustomed to reports of police violence. The Daily Sun, a South African newspaper, posted video the footage Thursday and it was quickly picked up by other South African news outlets and carried on the Internet. It sparked immediate outrage. "They are there for safety, but we as a people fear them more," said Johannesburg resident Alfonso Adams. "You don't know who to trust anymore."

The officers are set to appear in court on Monday.

For their part, the police accused Macia of obstructing traffic with his vehicle. They also allege Macia assaulted a constable and took his weapon before he was overpowered.

Some of those in the crowd who watched the scene unfold in the Daveyton township east of Johannesburg shouted at the police and warned that it was being videotaped. The police did not seem at all concerned by all the witnesses and the presence of cameras.

"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?"

Police watchdog launches murder probe

Macia's death has prompted a fresh wave of outrage at police brutality in South Africa, especially in Daveyton, near Johannesburg, where the dragging took place. (AP)

On Thursday, the Independent Police Investigative Directorate - a South African police watchdog -- said a murder probe is underway on the evidence that Macia suffered head and upper abdomen injuries, including internal bleeding. The injuries could be from the dragging and he could also have been beaten later in police custody, the group said.

"The allegations are that he was dragged behind a vehicle and his head was bent on the police vehicle. There are also allegations of assault," said the investigative unit's spokesman Moses Dlamini.

The video evidence of the abuse 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.

"As horrific as it is, it is not exceptional. Hardly a week goes by without such stories of brutality," said Jacob van Garderen, national director of Lawyers for Human Rights. Chief Phiyega has tried to upgrade the reputation of the South African police since her appointment last year. 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."

The problems, though, are immense for a police force that has expanded from some 120,000 to almost 200,000 over the last decade, "often failing to match the increase in quantity with sufficient quality," said Johan Burger, who served for 36 years on the force before becoming a senior researcher at the Institute for Security Studies.

Several experts contacted by The Associated Press also said that in recent years there has been an increasing willingness to use a shoot-to-kill approach to the crime and violence.

An average of 860 people a year died in police custody or as a result of police action between 2009 and 2010, up from 695 a year from 2003 to 2008, according to Burger of the security studies institute.

Further staining the reputation of the police is the Marikana shootings when, on Aug. 16, 2012, a line of South African police opened fire on a crowd of striking miners, killing 34 at a platinum mine northwest of Johannesburg. A judicial commission is investigating allegations that many were killed on a rocky hill, near the much-filmed initial scene of the attack, shot in the back as they tried to escape.

With files from CBC News