Yes, I think he could have. He didn't want to cover his tracks. Leaking information to the media is falling-off-a-log easy. The best journalists will tell you to your face "I'll go to jail before I give up a source"
It's not a matter of a journalist giving up his source. The issue is the sheer quantity of data leaked and the fact that the systems are (I assume) audited. Barring a security exploit I assume it would have been trivial to identify the responsible accounts.
If you believe otherwise I'm open to your theory but I think it is on you to provide a plausible explanation here.
