West Papuan independence advocates have accused Indonesian police chief Untung Sangaji of the torture and killing of peaceful activist Kristianus Yandum, who died on Saturday.
The National Committee for West Papua (KNPB) said Mr Yandum was among 13 of its members arrested on December 13 for merely sitting in front of its offices.
Mr Sangaji denied that the death occurred through torture and said Mr Yandum died in hospital from a congenital disease after receiving treatment there for several weeks.
"What should be noted is that while being treated at the hospital the person concerned was not even handcuffed, even though he was a prisoner," the regional police chief said.
He said that those being held "were treasonous and had continued to spread propaganda," but claimed that stories of detainees' ill treatment were a hoax.
KNPB spokesman Victor Yeimo insisted that the prisoners had been tortured and demanded that Indonesia's National Commission on Human Rights investigates.
"Untung Sangaji is a murderer responsible for the death of our friend Kristianus," he said.
"We strongly condemn the actions of police chief Untung Sangaji and call for humanitarian solidarity and justice for the victims, as well as the unconditional release of our 12 friends still languishing in the Indonesian police compound," he said.
He called for international pressure on Indonesian President Joko Widodo "to stop violence against KNPB peace activists and immediately take a peaceful political solution to the political conflict that continues to consume relentless casualties in the West Papua homeland."
At least 500,000 people, mainly West Papuans, are believed to have been killed since the archipelago was formally annexed by Indonesia in 1969.
Just over 1,000 West Papuans were forced – often at gunpoint – to ratify rule by Jakarta by voting for the so-called Act of Free Choice.