This is my first post because I've just gotten pretty fucking pissed off at the ignorance here.
Let me clear something things.
NO, we cant' be sure it's a "hacker". A hacker is a skilled individual, but ANYONE can spoof an e-mail address in 7 seconds and send somebody a malicious file.
And NO, Tom isn't going to try and find out who did it because again, ANYONE can do this. And even if it was possible for him to find out, there'd be no point because:
1. There's nothing he can do.
2. ANYONE can do it again anytime they'd like to.
Thank you very much, even though people are more than likely to just post stupid questions / remarks without reading the last freakin' page.