It's conceivable that, at some point, building design frameworks for friendly artificial intelligences (or, more plausibly, artificial intelligences in general) might be made illegal, but it certainly isn't illegal now.
http://en.wikipedia.org/wiki/Steve_Jackson_Games,_Inc._v._United_States_Secret_Service
Legality really doesn't seem to be a huge factor in whether the Secret Service can inconvenience you. And if they raided a gaming company, I could see them plausibly raiding an AI development organization.
That said, I don't see anything to suggest it's particularly likely, but a government investigation, all by itself, is incredibly disruptive even if you don't end up guilty of any crimes.
Edit: Fixed from FBI to Secret Service.
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