Videos posted online show an Iranian teenager protesting hours before her death, her mother has told BBC Persian.
Nika Shakarami, 16, is seen standing on a dumpster and burning her headscarf in Tehran on 20 September, as others chant slogans against the Islamic Republic.
She later disappeared after telling a friend she was being chased by police.
Her mother, Nasrin, also denied she was in a CCTV video put out by officials to support their claim that her death was not connected to the protests that day.
Mrs Shakarami has accused security forces of murdering her daughter, but officials have said she died after being thrown from a building that was under construction, possibly by workmen.
Last week, Iranian state TV broadcast blurry footage showing a teenage girl or woman whom it identified as Nika walking down an alley and entering a building through a door.
But Mrs Shakarami told BBC Persian on Monday that the person in the video was not her daughter. Another source close to the…