Probably lying to launder money. It's not a small number of coins, don't imagine they'd be sophisticated enough to hide those wallets. Really easy way to suddenly introduce millions of dollars in a suitcase and say, "oh, I just sold all my bitcoin on some marketplace somewhere, thank you very much".
Your post is the most correct. Bull's-eye! In Ukraine, there was a case when a parliamentarian announced that he had won his millions in the lottery. And he won the jackpot several times in a row - "lucky". In Ukraine, officials know how to launder money stolen from the state.