The family of an Aboriginal man who died while in custody say he was beaten by police officers before his death.
Terrance Briscoe, 28, died in the Alice Springs watch-house on Thursday.
Police say they found him unconscious in his cell at about 2am. Paramedics were unable to revive him.
The ABC reports Mr Briscoe was taken into protective custody on Wednesday night for being drunk.
His family say police told them he fell over and sustained a head injury before being locked away.
But they claim other people in the watch-house at the time witnessed him being assaulted. They say five officers were involved; four male and one female.
Police officials say they will not comment because the case has been referred to the coroner.
Family members have written to Chief Minister Paul Henderson, asking him to launch an independent investigation.
He says there will be a full police investigation into the death.
The Northern Territory Police Association says police investigating the death must follow strict guidelines established by a Royal Commission into Aboriginal Deaths in Custody.
The ABC reports Mr Briscoe's family has a history of dealing with Aboriginal deaths in custody.
His late aunt Letty Scott fought a 20-year legal battle over the death in custody of her husband, Douglas Scott.
Another aunt, Patricia Morton-Thomas, says the death of her nephew shows the recommendations from the Royal Commission are still not put into practice.
Ms Morton-Thomas says he was the victim of police brutality in the past.
''About four weeks ago Terrance came home,'' she said. ''He had a huge gash on his forehead, he'd been beaten around.
''When we asked him what had happened, he said two police officers had beaten him, one of whom was an Aboriginal officer, which is just disgusting.''
Police are not commenting on the accusations of brutality.