And it's quite possible that money talked at length and with great elogquence in that case. The Ministry is known to be willing to bend rules for the right reasons and it's unlikely that it wasn't so in the immediate aftermath of Voldemort's fall. It's also quite possible that the laws of the land forbid compelling the use of certain magics except when the evidence is overwhelming anyway.
Logic does not necessarily apply in law or in politics.
Logic does not necessarily apply in law or in politics.