My guess would be that they didn't have a search warrant the first time they came to speak with him-- they just asked permission to come in and ask some questions. Then they worked all night crafting the warrant so it was perfect for their wishes, and then came back once they had it.

Decius wrote:

I didn't sleep at home last night. It's fair to say I was rather shaken up.I came back today, to find the glass on the front door smashed.Inside, is a rather ransacked home, a search warrant taped to my kitchen table, a total absence of computers - and various other important things.

So, they go to his house yesterday, talk to him, and then leave... And then they return in the middle of the night, break in, and take his stuff?! Why didn't they just seize stuff when he was there in the afternoon?

RE: slight paranoia: FBI Visit #2