I do some interviewing for my company sometimes. HR people suck at it, but they don't ask any forms of technical questions.
So it'd be strange to have such deep questions asked by a non technical person for such a high position.
Secondly, I was interviewed by Google once. The interview was great (even though I failed it).
Third, during this interview, I signed a kind of non disclosure.
On the other hand: I was also interviewed by Microsoft. The interviewer was non technical, and asked at least two tech questions (the difference between a struct and a class in C++, and what volatile meant). And, finally, Roy Osherove has a similar tale about Google.