YouTube personalities ProSyndicate and TmarTn have been accused of illegally promoting a Counter Strike GO weapon skin gambling website to their joint audience of over 11 million subscribers, after it was discovered that the pair own the site in question and failed to disclose that information.

Both YouTubers have posted numerous videos showing them successfully gambling on CSGOLotto.com, a site which allows Counter Strike players – including those under the legal gambling age due to a loophole the site exists in – to gamble with weapon skins which have real-world monetary value.

TmarTn, real name Trevor Martin, is CSGOLotto's president, while ProSyndicate, real name Thomas Cassell, is the Vice President. This discovery of filing documents for the company was made by YouTuber HonorTheCall and helped spread by h3h3Productions.

Counter Strike GO (CS:GO) is an online shooter developed and run by Valve. The game includes weapon skins which are found in crates that randomly drop in the game and are opened with keys bought by players for roughly $2.50 a pop through Steam, the digital sales platform owned and run by Valve.

The rarity of the skins unlocked this way determines their value, and they can be sold through Steam's marketplace and then "cashed out" through buying games as gifts and selling the download codes on.

CSGOlotto.com allows players to gamble these skins, almost like chips in a casino, against other players. A slot-machine-like random number generator then decides a winner. Other websites allow these skins to be bet on the outcome of competitive CS:GO matches.

Valve does not endorse such websites, but has been accused of facilitating their existence in a class-action lawsuit that was filed against them in June. In April Bloomberg estimated that around $2.3bn worth of weapon skins were used in bets through websites like CSGOLotto in 2015 alone.

Neither TmarTn nor ProSyndicate disclosed their relationship to the website in any way in the videos they created - though they have since edited declarations into the descriptions. This may be in violation of US Federal Trade Commission (FTC) regulations relating to endorsements on social media sites.

[Warning: There is strong language throughout the following video]

The pair's link to the company also gives them access to the website's back-end, leading to accusations that they may have manipulated the results of their bets to create videos - such as "WINNING BIG $$$$!!! (CS:GO Betting)" - in which they win thousands of dollars' worth of skins.

TmarTn has since posted a video declaring his innocence, saying his ownership of the site was "never a secret". He has also claimed that he had no affiliation with the site at the time of uploading some of his videos - something proven untrue by the documentation that didn't just name him as a founder of CSGOLotto, but also as the one who filed the documents.

In one early video TmarTn says: "[A friend] has been hitting me up and we found this new site named CS:GO Lotto." He then repeatedly refers to the site as a separate entity, not in the terms of someone who owns the website.

He has also been making a number of his CSGOLotto videos private, evidence of which can be seen here. One such video can be seen here on another user's channel. In the video, Martin can clearly be seen logged into the CSGOLotto site as one of its bots.

ProSyndicate meanwhile has tweeted in response to the accusations: "I apologise to anyone who feels mislead regarding the ownership of CSGOLotto. I will always be more transparent from here on out! I do however stand very firmly behind the fact that CSGOLotto has never & will never scam/steal from players."