If we take AVP-R into canon - hey don't shoot the messenger - they probably send a cleaner in to erase any tracks left by incompetent Predators. The only reason Wolf's Plasma canon was left behind was because he was the cleaner and there was no one left after him to clean his shit up. Yea so whenever a predator losses something, some other predator pushes a button and it self destructs. The Governments cover story, it was a gas explosion.
Although I'm with Hicks on this, the Predators are nothing more than Dick Cheney if he did cross fit.