Say 'No'. Call a lawyer. Refuse to make any statements whatsoever.
If you think this is bad advice, call a lawyer and ask them.
If guilty, this is great advice.
If innocent, listen to what they say, answer truthfully, and go about your merry way.
I've been detained and questioned a few times in my life for things I wasn't involved with. If you have nothing to hide, and are indeed innocent talking isn't a bad thing. Of course, no one's ever accused me of a serious crime either, so maybe in such a situation I'd go with the lawyer thing.