According to GameIndustry.biz the primary hacker is German, but denies actually stealing the valuable source code.
“While it was confirmed last month that arrests had been made in a number of countries in relation to the source code theft – which was at one point implied to be the cause of the severe delay to the game’s completion, although Valve has since confirmed that they were not close to finishing the game at the time – no detailed information about the suspects or the case against them was released.
