Which family member?

Materazzi finally revealed that he insulted Zidane's sister, which led to that infamous headbutt and the sending off of Zidane during the World Cup final.

Most newspaper sport pages reported this news and the Telegraph was no exception. But curiously, the caption to a photo of Materazzi which accompanies the news article says "Materazzi: insulted Zidane's mother prior to headbutt"