I think he just wanted to vent his frustration after losing at a casino, and all he wrote was fiction. It would be a big surprise for me to show up here again sometime, and even more surprising if he had any evidence to back up his words.
judging by how he came and posted the scam accusation then left, I guess it is the most likely scenario. also, It's not the first time I've seen gamblers make up stories about them being scammed or how the casino is not fair/rigged after losing a sizable amount of money.