Some folks have basically gone into a trance flying drugs up from Columbia. The route is littered with their planes. The featureless surface of the ocean can lure you lower without your being aware of it especially if you are not used to low altitude flying. Sort of the same thing that sometimes happens to folks on a long distance interstate trip. Just my two bits, I am a pilot.
Sounds like some sleuth detective work needs to be stepped up. Look deeper into the backgrounds of those connected to this flight.