FE Hoppy
Whilst I would search the homes of the two flight crew, it would be to eliminate, as things stand now.
Having dealt with thousands of criminals, bigtime and smalltime, my instinct on this is that the crew were not involved. They are clearly both intelligent men and would be highly unlikely to do anything so stupidly obvious as to build. A simulator in their house and tell the world. They'd do it on the QT. And the pics I've seen, where he shows all the PC hardware in boxes is not in keeping with a criminal mastermind, just a bloke who loved his hobby.