The cellphone footage, posted on YouTube and obtained by the Daily Sun, portrays police shows a Mozambican taxi driver handcuffed to the back of a South African Police Service van in Daveyton and being dragged for more than 400 yards, the Independent Online reported Thursday.
The man later died, officials said.
"We are still interviewing the witnesses because the allegations are that he was dragged with the police vehicle," directorate spokesman Moses Dlamini said.
The police directorate said it also was trying to find the person who shot the video to "authenticate the footage."
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