South African police have been accused of planting weapons near the bodies of strikers killed at the Marikana platinum mine. Photographs appear to back the accusations.
A awyer told an inquest into the deaths on Tuesday that photographs taken by police suggested large knives had been placed near the bodies after they had been shot,.
Thirty four miners died when police opened fire on striking miners on 16 August. Police said they were acting in self-defence.
The BBC reports a dead man is shown lying on rocky ground near the mine in one photograph. A second picture, taken later the same day, is identical except a yellow-handled machete was lying under the man's right hand.
"The evidence clearly showed there is at least a strong prima facie case that there has been an attempt to defeat the ends of justice," lawyer George Bizos told the inquest, according to the Sapa news agency.
Police lawyer Ismael Semenya told Sapa that national police commissioner Riah Phiyega had begun an investigation into the accusations.
He said police authorities had been aware of the photographs since they were handed to the inquiry two weeks ago.
A BBC correspondent in Johannesburg says the court also saw video footage which showed the bodies of miners with their hands handcuffed behind their backs.
Some 270 of the striking miners were arrested and charged with murder, though the charges were later dropped.
The strike ended in September after workers agreed a 22% pay rise with Lonmin, the mine's owners.