The panel says police falsified or withheld documents in an attempt to cover up what happened at the Marikana mine in August 2012, the BBC reported Thursday.
The accusations were made 10 days after a senior policeman turned over a personal hard drive with information the panel said contradicted statements and evidence presented by other officers.
"We have obtained documents which the SAPS [South African Police Services] previously said were not in existence" which "demonstrate that the [police] version of the events at Marikana ... is in material respects not the truth," the commission said in a statement.
The commission, which has not completed its investigation, said the new information had "serious consequences" about the panel's ability to continue.
The commission adjourned until Wednesday, saying it had "thousands of pages" to review.
Police portrayed the illegally striking miners as responsible for the violence. Some 270 miners were arrested and charged with murder, although the charges were later provisionally dropped.
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