this isnt some "he fit the description, and doesnt have an alibi, so we think it's him"
this is an electronic trail leading to one person, HIM
so the only options is that it is either him or someone set him up.
Which is surprisingly easy to do, I can send a email from your address real easily
Now, look at all the emails that where circulated about Palin that turned out to be fake, or even browse through Snopes, it is full of tons of fake emails.
There are a lot of people that would like to see a Democratic Senators son implicated in this. Yet the person that actually did do it took the time to cover his tracks pretty well. It's not a stupid person, and whoever it was must know that if they get caught they would be in some legal trouble. Now if your dad is a politician, this would likely effect his career as well.
So really, why on earth would he confess had he gotten away with it?
And if he had, and the FBI had questioned him would it do any good at all to deny it?
As far as questioning him goes, of course he got questioned. I could circulate a email from you confessing and I suspect you would get questioned, they wouldn't be doing their jobs if they didn't.