I am also curious how David Clarke knew Satoshi.  He seemed like a nice guy, above board and all.  Why would he have known a guy like Satoshi, and why would he know that Satoshi would provide the means for revenge?  I think that Nolan knows a lot more than he is letting on.  After all, he just appears and has access to all of David Clarke's stuff and secrets, and he doesn't know anything else?  Also, we can't even be sure what his agenda is in all this.  We know he is lonely without friends, but why would he risk his neck over and over again when he has no interest in the revenge scheme?  Unless he does somehow...and maybe that will be revealed later on.