Wait, what? They're actually taking the money? I thought the article was just being careless with the terms "frozen" and "seized".
On what power are they doing so? It's understandable when the relevant authorities (be it a tax authority, or a financial supervisory authority, or a court, or whatever) seize money, but they are not an authority.
Furthermore, if the money in question actually were illicit, then by what fantasy argument would they be allowed to keep it themselves rather than having to hand it over to the goverment? The entire point is that the money is dirty and nobody may keep it.