In the aftermath of the Zidane head-butt incident, there was a lot of speculation over what Materazzi might have said to provoke Zidane's response.
Zidane has said he attacked Materazzi because he insulted his mother and sister. Materazzi denied disparaging Zidane's mother.
I immediately noticed the very precise denial from Materazzi. (I suspect any parent would recognize the same thing.) And my suspicion was vindicated earlier this week:
Italy's Marco Materazzi said he insulted Zinedine Zidane's sister.