The US Department of Justice building in Washington, DC, is seen in 2019.
CNN  — 

A former US Army soldier was sentenced to 45 years in prison for his role in plotting to kill fellow service members at a US military base in Turkey.

Part of a neo-Nazi, pro-jihadist group known as the Order of the Nine Angles (O9A), Ethan Melzer, now 24, provided sensitive details about his unit, including locations, security and troop movements, to the extremist group in connection with its plot to attack the base and kill his fellow soldiers, according to the Justice Department.

According to prosecutors, Melzer’s motivation for the attack was to cause a mass casualty event, bringing on another war in the Middle East and “ultimately a race war to advance his mission of white supremacy” and the downfall of Western civilization.

In June, Melzer pleaded guilty to attempted murder of US service members, providing material support to terrorists and illegally transmitting national defense information. He had pleaded not guilty in 2020 to charges that he was planning a mass casualty attack on his own unit by sending sensitive information to the extremist group.

“I’m sorry, and I regret every single thing I did,” he told federal judge Gregory Woods during the plea hearing last year.

Members of O9A have espoused violent, neo-Nazi, antisemitic and satanic beliefs and have expressed admiration for Nazis, including Adolf Hitler, and Islamic jihadists, including Osama bin Laden, according to prosecutors.

According to Melzer’s defense attorney, Jonathan Marvinny, Melzer discovered the O9A group online in early 2019 – three months after he had enlisted in the US Army – and, after being “confined to his barracks” in Italy during the pandemic, began “drinking heavily, and spending far too much time online.”

Before Melzer was part of the OA9 group, he had an interest in “the occult” and joined online occult-related message boards, eventually coming across the group, according to court documents.

Plans to attack his unit slowly changed to attacking a replacement unit and then to attacking the sensitive military installation itself, which Melzer learned he would be assigned to guarding, court documents say.

“As soon as Melzer learned of his unit’s impending deployment to a sensitive location in the proximity of jihadist forces, Melzer treasonously turned to plan an attack on the very soldiers he was entrusted to protect,” prosecutors wrote in a sentencing memo. “He revealed highly sensitive – and largely classified – information to other O9A members and jihadists in order to murder his fellow soldiers in an ambush.”

According to the Justice Department, Melzer shared the sensitive information he learned about the base prior to deployment with O9A as well as a purported member of al Qaeda.

Marvinny wrote in a letter to the judge that O9A was “uniquely incapable of carrying out any real-world action” and that the leader of a sub-group Melzer joined was a 15-year-old Canadian boy who pretended to be an ex-paratrooper online.

Melzer received the maximum, aggregated sentence for his charges.

CNN’s Sydney Kashiwagi contributed to this report.