Apparently, somebody set up us the bomb. Random explosions kept taking people out. We had spies working on the source of the problem, but with little success.
I saw an explosion happen in the post office. I went to check it out, and found at the site burnt remains of the enemy plans. It seems that some of our spies were double agents and that what we were seeing was the stereotypical "This message will self-destruct in X seconds" gone horribly wrong.