The death in police custody of a disabled Aboriginal man continues to reverberate, with groups calling for an "immediate, independent, and transparent inquiry" into his death.

On Tuesday, a 24-year-old man from the Yuendumu community died after being restrained by police inside a Coles supermarket in Mparntwe/Alice Springs.

Warlpiri Elder Ned Jampijinpa Hargraves said the man who died was his jaja (grandson), and "Warlpiri people and many other people here in Central Australia are devastated by this death".

"I am angry and frustrated that yet another one of our young men has lost his life at the hands of the police," he said.

"We are demanding answers and justice. We know that he was held down by two police until he lost consciousness and perished. But at the moment, we are in the dark about what really happened."

Responding to comments from NT Police, who have not commented on the actions of the officers but on the alleged offences of the young man, Mr Hargraves said: "It is disgraceful that police are already putting out stories that portray my jaja as a criminal. We are always told by lawyers that we need to wait for investigations to take place before we comment on events."

"But police have not waited - they are trying to run him down. We demand they stop spreading stories and show some respect," he added.

Police said they "restrained the adult male" after an altercation with a security guard at an Alice Springs Coles; however, the male "stopped breathing and CPR was commenced".

"St John Ambulance attended the scene, and the man was conveyed to Alice Springs Hospital, where he was pronounced deceased shortly after 2:20 pm," NT Police said.

Uncle Rodney Dillon, Amnesty International Australia's Indigenous Rights Spokesperson, said the organisation "stands with the Yuendemu community who will be grieving the loss of another young man who was brutally killed by police officers using excess force".

The man is the eighth Indigenous person to die in custody this year, and at least the 593rd to die in custody since the 1991 Royal Commission.

Not one person has been found guilty in connection to any of these deaths.

The man was revealed to be disabled and under state care when he died in police custody.

"This young man was living away from his community, in town, in supported accommodation because of his disabilities, and he was very vulnerable," Mr Hargraves said.

"He needed support and not to be criminalised because of his disability.

"What are the police doing using such force on a vulnerable young man in a supermarket? Did they even try to de-escalate?"

On Wednesday afternoon, NT News reported witnesses had said police had put their knee on the man's neck, despite his friend calling out: "Hey, look, this fella has a disability, he's disabled, just be a bit more careful."

"There was an Aboriginal man on the floor, and a police officer had his knee behind his head," the witness said.

"If they had sat him up, had his hands behind his back and let him sit up for a minute — Not keep him down on the ground," they added.

Assistant Commissioner Travis Wurst told reporters on Tuesday: "The male behaved rather aggressively and was placed onto the ground by those police officers," who were plain-clothed in the supermarket.

NT Police have not explained how restraining somebody can lead to their death, what restraint they used, or what the meaning of "placed on the ground" means.

Writing on her Substack, journalist and author Amy McQuire noted that "placed on the ground" makes the "act seem innocent, even benevolent".

Noting there has been no CCTV footage and the only information has come from the police, she added: "Given the vast majority of cases I have witnessed, I would question this idea that this man, who 'lost consciousness' and 'stopped breathing' was simply 'placed on the ground'."

Assistant Commissioner Wurst said the investigation would be led by a police commander from Darwin "to ensure it's done independently and transparently".

However, there is already criticism that independence isn't just police from a different jurisdiction investigating the actions of their counterparts.

In a statement, an Amnesty Australia spokesperson called for an "immediate, independent, and transparent inquiry" into the death in police custody.

"It is imperative that the investigation is conducted by a body entirely separate from the Northern Territory Police to ensure impartiality and to maintain public confidence in the process," a spokesperson said.

"The death of yet another young Aboriginal person in police custody is unacceptable and demands immediate action."

Mr Dillon said there's "no justification for police to use force against someone that is so brutal that it cuts off their breathing and kills them".

"The use of excess force by NT police must be independently investigated, and the findings from the inquiry into this death, the death of Kumanjayi Walker from his same community and from the 1991 Royal Commission into Aboriginal Deaths in Custody must be fully implemented."

Warlpiri-Luritja man Kumanjayi Walker was shot and killed in 2019 by former NT police officer Zachary Rolfe.

Mr Rolfe was found not guilty on all charges in 2022.

The long-awaited findings into the inquest of Kumanjayi Walker, which has heard accounts of police racism and violence, are due to be handed down by Coroner Elisabeth Armitage on June 10 in Yuendumu.

Federal Lingiari member Marion Scrymgour said the man's death was "being felt heavily in our community".

"An investigation is underway - but one thing is clear - we all need to come together during this time," she said, as reported by NT News.

Mr Hargraves said they will be "calling for action from supporters to demand accountability, justice and self-determination".

"We can not tolerate this situation, with continued brutality and lack of respect," he said.

"The deaths and the racism need to stop."

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