Johannesburg (CNN) -- A man, struggling to get away, is surrounded by South African police in the middle of a street as a large crowd looks on. The officers pull him over to a police van and handcuff his hands, over his head, to the back of the vehicle as he sits on the ground.
Soon, as some in the crowd scream, the van begins to move. It slowly picks up speed. The helpless man in a red T-shirt is dragged along the road.
Soon, two officers lift him up by the legs, apparently to avoid dragging -- but the police van seems to speed up, and the man's legs fall to the ground, He is dragged hundreds of feet.
Though injured, the man was never taken to a hospital, police investigators say.
He died a few hours after the incident. The suspected cause of death: head wounds.
The video, captured by someone in the crowd in Daveyton, near Johannesburg, has sparked fury over police brutality in the country.
"We are shocked by this incident," said Moses Dlamini, a spokesman for the Police Investigative Directorate, an independent government agency that looks into possible crimes by police.
But such a scene may not be all that rare. The directorate received more than 6,000 complaints accusing police of numerous crimes, including murder and torture, during a one-year period from early 2011 to early 2012.
The cases include 648 deaths.
The U.S. State Department's human rights report on South Africa for 2011, the latest year available, said the country's "principal human rights problems included police use of lethal and excessive force, including torture, against suspects and detainees, which resulted in deaths and injuries; vigilante and mob violence; and prison overcrowding and abuse of prisoners, including beatings and rape by prison guards."
But Dlamini was quick to emphasize that in the nation of 50 million people, police who carry out crimes do not reflect the police service as a whole. "There are many other officers who are dedicated, who uphold the law and arrest criminals all the time," he said.
While authorities have not confirmed the man's identity, local reports say he was a taxi driver from Mozambique.
The man and the police in the video, as well as those in the crowd, are black, so there is no suggestion that the incident is a sign of white vs. black tensions in the country.
"This appalling incident involving excessive force is the latest in an increasingly disturbing pattern of brutal police conduct in South Africa," said Noel Kututwa, Amnesty International's southern Africa director.
Johan Burger, a senior researcher with the Institute for Security Studies in Pretoria, said some police officers think they "are above the law" and that there won't be consequences for their actions.
South Africa's history of violence "is part and parcel of daily life," he said. Some think "the best way to deal with this is to act in a brutal way."
CNN's Nkepile Mabuse reported from Johannesburg; CNN's Josh Levs reported from Atlanta.