I was playing 10/20. It was going fine and I was winning a bit. One hand, villain raised to 100+. Everyone folded to me. I had 55. I asked villain how much he had left, he showed 300+ total including his raise. I put him all in and he called. We were heads up so by my count, pot was 600+. He had KK which was fine. He took down the pot. So he had around 600.
A few hands later, I saw that he wasn't in his seat but chips in his place were just 330. He hadn't played any hand since his KK so I was wondering where his chips went. He came back and I saw that he had 300 in his hand. This was ok. Then after a few hands, I saw him stand in his place and put his hand in his pocket. After that, I can clearly see that he no longer has any chips in his hand and the only chips he was playing with was the 330 in front of him.
I wanted to be real sure that he kept the chips so I was waiting for him to play. Within the same orbit, he went all in (330) with JJ against an opponents QQ. (I'm not sure about the cards because by this time I was on tilt.) He had never played another hand so he should have more than 300 with him.
After I saw him go all in with only 300+, I stood and went to the floor manager on duty and told him about it. I'm not sure what happened after because they need to check the recording but I swear that he kept those chips. I would stop playing poker if I'm proven wrong.