Indonesia's National Commission on Human Rights, Komnas HAM, reports it has found at least 96 participants at last month's Papuan Peoples Congress were assaulted by police.
The Commission's chair, Julles Ongge, says it interviewed Congress participants and found 96 of them had been assaulted but he says there may have been more.
The Jakarta Post reports that the investigation also found police had seized millions of rupiah from participants, four cars and some electronic equipment.
Police also destroyed seven motorbikes and confiscated dozens of mobile phones.
Mr Ongge says the Commission will use the findings to produce a report detailing possible human rights violations that took place during the Congress.
He says police have denied accusations they shot at six civilians attending the congress, but the Commission has eyewitness accounts testifying the officers did shoot at the participants.