"I would just like to thank the whole Australian community for the support you have showed," wrote 18-year-old Dylan Voller, in a letter released by his lawyer.
"I would also like to take this opportunity to apologize to the community for my wrongs and I can't wait to get out and make up for them."
In a video shown on Australian Broadcasting Corp.'s "Four Corners
" investigative program, Voller was seen hooded and strapped to a chair half-naked in what a lawyer described to ABC
as Guantanamo Bay-style treatment.
Voller, then 17, had a hood placed over his head, and his ankles, wrists and neck were shackled in a detention center in Alice Springs in 2015 after, authorities say, he threatened to hurt himself, ABC reported.
Other footage from detention centers across the Northern Territory showed boys as young as 10 being tear-gassed, stripped naked and kept in solitary confinement.
In the letter, Voller thanks ABC and "Four Corners" for their help, along with his lawyers, "in getting the truth out there to the public."
The program showed videos of abuse taking place at several centers across the Northern Territories, including the Don Dale center in Darwin.
The revelations in the "Four Corners" program have sparked outrage in Australia, with Prime Minister Malcolm Turnbull promising a government investigation.
Northern Territory Chief Minister Adam Giles said that police have formed a special task force to look into the allegations raised by the program.
The investigation "must be as expansive as possible," Peter O'Brien, a lawyer representing Voller and another boy, said in a statement.
"It needs to scrutinize all tiers of the Northern Territory prison hierarchy, from the guards who perpetrated the abuse right up to the Chief Minister," he added.
O'Brien called for Voller, who is currently being held in an adult prison, to be "released immediately."
"The impact of these years of brutalization must be immediately measured and he needs immediate assistance," he said.
Sky News reporter Dan Bourchier told CNN that the government investigation -- a royal commission -- will "look at the juvenile justice system as a whole across the Northern Territory."
Use of restraint chairs suspended
The use of spit hoods and restraint chairs in juvenile detention centers in the Northern Territory had been suspended until the national investigation is completed, said Giles, the chief minister, according to CNN affiliate Sky News
Giles has been under added scrutiny this week over comments he made in 2010 about putting criminals in a "concrete hole."
According to Sky, while in opposition he told parliament in 2010 that he would "love to be the corrections minister."
"It is not the portfolio I really aspire to but, if I was the prisons minister, I would build a big concrete hole and put all the bad criminals in there: 'Right, you are in the hole, you are not coming out. Start learning about it.'," he said at the time.
"I understand there are rules which guide the prisons in Australia and the United Nations, and how we use basic human rights in the treatment of prisoners ... what I do not understand is how we are soft, flaccid, and incapable of punishing prisoners in our corrections system.
"I might break every United Nations' convention on the rights of the prisoner but 'get in the hole," he said.
After the comments were widely circulated on Twitter in the wake of the "Four Corners" report, Giles told Mix 104.9 FM in Darwin that he was "vent(ing) my frustration."
"I'm now chief minister, I take responsibility for the whole lot of government and past governments who created injustices."