[email protected] expired somewhere in 2011~2012 (gmx remove account within one year of inactivity), and someone immediately took it, and then used it to take control of Satoshi's account on p2pfoundation and bitcointalk.

But even without knowing that, Satoshi had no reasons at the time to came back just to say that one particular guy was not him, just on p2pfoundation and without any kind of proof.