A man has been extradited from Melbourne and will be charged with the murder of a teenager in Alice Springs over New Year's.
The body of the 19-year-old victim, believed to be of African descent, was found by a driver on a remote road near Undoolya Station at midday on January 1.
Northern Territory Police successfully applied for the extradition of a 22-year-old man from Victoria on Sunday.
He is being flown back to Alice Springs on Monday, where he will face court charged with murder.
A 17-year-old boy and a 21-year-old man have been charged with accessory to murder after the fact and are also set to face court on Monday.
The pair were in police custody for 144 hours without a charge, with the NT being the only jurisdiction allowing police to hold suspects for more than 48 hours pre-charge.
NT Police Assistant Commissioner Travis Wurst said the victim and accused trio were known to each other but police were still investigating if weapons were used.
"The forensic pathologist has advised us that the cause of death relates to blunt force trauma," he told reporters in Darwin on Monday.
"There aren't any penetrative wounds on the deceased.
"All items that were seized from the crime scene are being examined."
Mr Wurst said police are also searching for a video allegedly showing the victim being assaulted before his death.
"This is a short video which has circulated amongst a small group of people in Alice Springs," he said.
Police said other graphic videos circulating in Alice Springs depicting "beheadings" and assaults from other countries were not relevant to this investigation.
"(The video) will be a significant piece of evidence ... making sure the persons charged... are brought to justice," Mr Wurst said.
A fourth suspect held by police over several days was released without charge over the weekend and police say there is no risk to the public.
Investigations into the death are ongoing.
