I don't know how it works...
Outside of the US, but under US law, a "work for hire" becomes the temporary property of the person who was contracted to do the work in the event they are not paid, under the "mechanic's lien" law. Assuming that the webmaster was, indeed, not paid, the buyer's act of redirecting the Web page thus constitutes theft, and may even run afoul of the few criminal laws governing the Internet.
If I were a stockholder in either the buying or selling firm, I should be demanding an immediate settling of accounts, to prevent seizure of assets - which is legal under a mechanic's lien.