That isn't a virus then that is locking it. That is something the police put on it. If this is the case, there is no way for you to unblock it unless you go through them. If you aren't guilty, you should, obviously, be able to fight it, and may get the fee reduced or waved. However they would have your phone locked until then.
So, in the end, the only way to access it, is to go through that police department.