Honestly... I am a bit disappointed in seeing the "solution" to this "puzzle". It isn't really any different to something like:
Q. WhyDidTheChickenCrossTheRoad?.txt
A. BecauseItLikedCrossingRoads
As I said due the not related at all solution with a puzzle the how he got it seems to be:
- Alt Account
- Brutal Force
This is also supported by the fact that money are still on a virgin address.