Elon Musk has weighed in on the arrest of Australia's most decorated living soldier, Ben Roberts‑Smith, describing the development as 'insane' in a brief but high‑profile post on X. 

Musk, the billionaire owner of X and CEO of Tesla and SpaceX, responded on Tuesday to a viral post that reported Roberts‑Smith had been arrested over alleged war crimes linked to his service in Afghanistan. 

Roberts-Smith was charged with five counts of war crime - murder late on Tuesday afternoon and appeared briefly in court where he was denied bail. He was transferred to Silverwater Prison in Sydney where he will spend Tuesday night before he is set to appear for another bail hearing on Wednesday morning. 

Musk was responding to an X post made by Australian social media figure and conservative political activist Drew Pavlou, who was supportive of Roberts-Smith. 

Roberts‑Smith, a recipient of the Victoria Cross for Australia, was earlier arrested by Australian Federal Police officers at Sydney Domestic Airport on Tuesday morning after arriving on a flight from Brisbane.

New details indicate the retired SAS corporal was taken into custody in front of his teenage twin daughters, who were also on the flight with Robert-Smith's girlfriend as it was for a family holiday. 

Vision captured AFP officers escorting him on the tarmac shortly after the aircraft touched down, with officers waiting at the arrivals gate.

The charges follow a lengthy joint investigation by the Office of the Special Investigator (OSI) and the AFP into alleged unlawful killings during Australia's military deployment in Afghanistan.

Each offence Roberts-Smith has been charged with has a maximum penalty of life in prison. 

According to investigators, the charges are connected to alleged incidents in Uruzgan Province across multiple tours. 

Prosecutors allege Roberts‑Smith intentionally caused the death of a person during a April 12, 2009 operation at Kakarak. 

He also allegedly aided, abetted, counselled or procured another person to intentionally cause a death during the same operation.

Further charges are connected to a separate incident on or about September 11, 2012 at Darwan, where he is accused of assisting in the intentional killing of a person.

Authorities also allege Roberts‑Smith acted alongside another individual to intentionally cause a death on or about October 20, 2012 at Syahchow, as well as aiding or procuring a killing at the same location and date.

Among the allegations are that he shot dead one already-captured man and brought his prosthetic leg back to Australia to use as a trophy to drink beer. 

He is also accused of kicking a man, whose arms were tied, off a 10metre cliff before ordering another soldier to shoot him.

Roberts‑Smith earned the Victoria Cross in 2011 for what was officially described as extraordinary bravery, after single‑handedly assaulting Taliban machine‑gun positions to protect his fellow soldiers. 

For years, he was publicly celebrated as a national war hero, later becoming a prominent public figure and media executive.

'This is how we repay him?' Pavlou said in his X post.

'Tell me: When does the Taliban plan on holding war crimes tribunals into their own people? When do the Taliban plan on holding themselves accountable for terrorism?'

The arrest marks a dramatic escalation in a legal saga that has already reshaped Australia's understanding of its longest war. 

It follows years of investigative reporting, internal defence inquiries, and the establishment of the OSI to pursue potential criminal accountability arising from the Afghanistan conflict.

Prime Minister Anthony Albanese repeatedly refused to weigh in on Roberts-Smith's case during a press conference on Tuesday. 

'I have no intention of commenting on a matter that's clearly before the courts,' he told reporters. 'It is very important that there not be political engagement in what is a matter that is now the subject of legal proceedings, so I don't intend to comment.'

One Nation leader Pauline Hanson vowed to stand by Roberts-Smith in the wake of his arrest as she slammed authorities over the huge cost to reach this stage.

'I remain steadfast in my support,' the senator posted online.

'Ben, his immediate and broader defence family need the Australian people's support right now and I will not abandon him like so many other politicians.

'AFP and OSI have spent $300million over 10 years to get to this point.'

Greens leader David Shoebridge said his arrest 'highlights the appalling cost of war on all sides'.

The Office of the Special Investigator, comprised of 54 investigators, has been investigating dozens of cases involving allegations of war crimes by ADF members in Afghanistan.

Out of the 53 investigations, 39 have been provisionally finalised.

OSI director Ross Barnett said the cases were extremely complex because many of the allegations involved incidents more than a decade ago, in countries thousands of kilometres away and there were no post-mortem reports. 

Roberts-Smith will be the second Australian soldier to be charged with war crimes under domestic law after another ex-SAS soldier, Oliver Schulz, was charged in 2023 over the war crime of the 2012 murder of a young man in Afghanistan.

Schulz has maintained his innocence. His matter is yet to go to trial.