If you're not pulling my chain then this is very serious, much more serious than I think the person who took the torpedo realizes. Explosives are indeed fowned upon by the ATF among about another dozen alphabet soup agencies. Since the explosives are formed into viable munition, they are also looking at charges of terrorism and possession of a weapon of mass destruction under the new DHS laws. I know it sounds outlandish but I assure you I am not exaggerating. Under the current guidelines they can consider several propane tanks a weapon of mass destruction, and these torpedoes have about 600 lbs of tnt inside. Let me tell you from personal experience that if the government finds out they will be very harsh with these guys and will not stop with just them, there are TONS of agents trying to make a name for themselves...they will proceed to go through their phone, email, bank, and credit card records and see who they are associated with and who knew what.....I consulted to several government agencies on technical issues in this field (specifically concerning timing devices) and these guys are gung-ho. Not to mention that the explosives and mechanics may be unstable and could create a smoking crater where his lawnmower shed used to be, LOL.
If I were them, I would contact the local FBI office and explain to them the situation....I would also have a lawyer on retainer, a good one, haha...and then stand by for about a million vans, cars, trucks, troops, and helicopters to start evacuating the neighborhood.....I would also get comfortable with being on the news.
OR - leave it in a remote area and call the FBI to come get it......
Or you could just be telling a sea story since these things are about 25 feet long and too big to hide under your bed....
-Dan