It may be a long shot, but I think we could find out a lot from the "flight-data recorders" or black boxes, if they can (or are ever) found. I don't believe that the cockpits of any of those planes were quite...If any info is to come out on who did this I think it will come from these items.
------------------
Never try to teach a pig to sing; it wastes your time and it annoys the pig
I've got to admit it's getting better, it's getting better all the time
Bossman of Better Funny Stuff.....of the Laughing Hyenas!