Ben Roberts-Smith has collaborated with a gym supplements company run by a rightwing influencer which recently sold a pre-workout product called “war crimes”.

Roberts-Smith, one of Australia’s most decorated living soldiers who is currently awaiting trial on war crimes charges, has recently launched an apparel brand, Epic 1 Two, producing T-shirts and gym wear.

In October, he also appeared in a social media video collaboration between his brand and Zero Limits supplements, co-owned by the rightwing podcaster and fitness coach Chris Katelaris, also known as “Big Chocky”.

Roberts-Smith, Katelaris and others were filmed during a gym workout, with on-screen graphics reading “Zero Limits Supplements x Epic 1 Two”. Both brands were labelled “collaborators” on the video, which is also published on the Instagram grids of both brands.

Months earlier, Zero Limits had repeatedly posted online about a product titled “war crimes”, an energy supplement in the flavour “kill or capture cola”. Its label depicted a hooded captive on a chair in a room with an Australian flag on the wall, and a tall figure wearing a balaclava and military-style clothing.

In a video on 26 July, Katelaris promoted the product while holding a tub at the gym.

“You wanna drink out of a prosthetic leg? You wanna re-enact a Sparta kick? You wanna execute your workout?” he said.

“War crimes, it’s the pre-workout for you.”

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Zero Limits, which says it is “veteran owned and operated”, does not currently list the “war crimes” product on its website, and Roberts-Smith is not shown endorsing, referencing or using that particular product.

The former soldier has praised another product from Zero Limits, posting an Instagram story – since shared by the brand – from Epic 1 Two’s Instagram page of himself drinking a separate pre-workout drink.

Roberts-Smith gave the brand a “massive shout out” and told followers to “get on their website and take a look”, sharing a link to its website. Roberts-Smith also last week appeared on the Zero Limits podcast, hosted by another founder of the supplements company of the same name.

Roberts-Smith was in April arrested and charged with five counts of war crime – murder, in relation to three incidents stemming from his service in Afghanistan in 2009 and 2012.

He has denied the charges, saying in a statement after his arrest: “As I’ve always maintained: I categorically deny all of these allegations … I will be taking this opportunity to finally clear my name. I’m proud of my service in Afghanistan.”

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The three incidents allegedly involved Afghan nationals being shot dead by Roberts-Smith, or a subordinate under his command, while he was present, the AFP commissioner, Krissy Barrett, said in April.

Roberts-Smith was previously found in a defamation suit – using the civil standard of the balance of probabilities – to have murdered unarmed civilians while serving in the Australian Special Air Service Regiment (SAS) in Afghanistan.

The federal court found to the lower civil standard that Roberts-Smith kicked Afghan man Ali Jan in the chest, sending him falling backwards over a cliff before he landed on the ground. The court found that Roberts-Smith then ordered another soldier to shoot him dead.

Roberts-Smith was also accused in media reporting of shooting an unarmed prisoner who had a prosthetic leg. The leg was later used as a drinking vessel by soldiers.

Zero Limits, Katelaris and Roberts-Smith were contacted for comment.

In a statement via a lawyer, Zero Limits did not respond to specific questions, only answering: “The products are great, make sure you check them out.”

In a statement via the same lawyer, Katelaris also did not respond to specific questions, but said: “If you thought this was wild, wait until next week’s campaign drops.”

Katelaris lists himself as a “co-owner” of the supplements brand in his Instagram bio. He also promotes a range of merchandise under his own name in support of Roberts-Smith, including “I stand with BRS” T-shirts, hats, hoodies and stubby coolers.