You should consult with an attorney as soon as possible. If you are going to cooperate you need to understand what is going on, if not, you need to understand the risks. Either way, only a lawyer meeting privately with you can assess the situation and advise you properly.
As to the property it depends if it was seized or is being held as evidence. If it was seized it may be hard to get it back at this point, but you still need to consult an attorney in your area to determine your best course of action here.