Legal proceedings against the seller of illegal property

Hello.

You should sue the seller.

If you are the first buyer (the original owner sold it to you), your lawyer and the notary public who registered the transaction might be liable and it is easier to take your money back.

If you are not the first buyer; it is harder to take the money back because every middle hand will start to sue to get to the original owner and it is unlikely that your lawyer had a chance to find out about this.