He looks too tall to be riding itI think the guy was probably offered the bike cheap and knew it must be dodgy. He couldn't have bought it online either.
He then rode it for a few years and when he decided to sell took off the distinctive wheels and cranks to sell it. They were also the most expensive parts and probably easy to sell on.
I dont think he stole it and I doubt it was stolen to order as it was probably the only day I ever had a bike in the house. Which did fuel the paranoia even more though.
However, I still have absolutely no idea what went on really.