BERLIN (AP) -- Was it something he said?
With France and Italy tied in extra time of Sunday's World Cup final, Zinedine Zidane head-butted Marco Materazzi in the chest and was ejected. France went on to lose on penalty kicks.
The day after, still no one knew what the Italian defender might have said to the French star.
"The Italians did everything they could do to provoke Zidane," France defender William Gallas said.
Seconds before, Materazzi had grabbed a handful of Zidane's jersey just as a French attack on goal passed harmlessly by. The two exchanged words as they walked back up the field, well behind the play. Then, without warning, Zidane spun around, lowered his head and rammed Materazzi, knocking him to the ground.
The Paris-based anti-racism advocacy group SOS-Racism issued a statement Monday quoting "several very well informed sources from the world of football" as saying Materazzi called Zidane a "dirty terrorist." It demanded that FIFA, soccer's world governing body, investigate and take any appropriate action.
FIFA, which reviews all red cards at the World Cup, would not comment on the specifics.
"This is a disciplinary matter now. I can't give any statements now," FIFA spokesman Markus Siegler said.
Materazzi, meanwhile, was quoted as denying the terrorist comment.
"It is absolutely not true, I didn't call him a terrorist, I don't know anything about that," the Italian news agency ANSA quoted Materazzi as saying when he arrived with his team at an Italian military airfield.
"What happened is what all the world saw live on TV," the Italian player said, referring to the head-butting.
Zidane's agent, Alain Migliaccio, was quoted by the BBC as saying the France captain told him the Italian "said something very serious to him, but he wouldn't tell me what."
Whatever it was, it was enough to infuriate Zidane.
"Zizou is someone who reacts to things," said Aime Jacquet, Zidane's coach at the 1998 World Cup. "Unfortunately he could not control himself. It's terrible to see him leave this way."
Even with the ejection, Zidane still won the Golden Ball as the World Cup's best player.
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Zidane, who came out of retirement to help France qualify for the World Cup and said he would quit soccer completely after the tournament, got 2,012 points in the vote by journalists covering the tournament. The three-time player of the year beat Fabio Cannavaro (1,977) and Andrea Pirlo (715), both of Italy.
Zidane's red card was anything but unusual. He was sent off 14 times in his career at the club and international level.
At the 1998 World Cup, he stomped on a Saudi Arabian opponent. Sitting out a two-match ban, he came back to score two goals against Brazil in the final.
Five years ago with Juventus, he head-butted an opponent in a Champions League match against Hamburger SV after being tackled from behind.
The reaction to Sunday's outburst was mixed in France. President Jacques Chirac called Zidane "a genius of world football," and former Sports Minister Marie-George Buffet said Zidane's aggressive act was unforgivable for its effect on children watching the game.
"This morning, Zinedine, what do we tell our children, and all those for whom you were the living role model for all times?" French sports daily L'Equipe wrote.
Zidane, whose parents emigrated to France from Algeria, became a proud symbol of a multicultural France and is adored in Algeria.
In the mountains where Zidane's parents grew up, Atmanne Chelouah carried off a life-size cardboard cutout of the player at "Cafe Zizou" after the red card.
"We are very disappointed," Chelouah said. "He should have kept his cool."
But lashing out is nothing new to Zidane, who grew up playing on concrete in an impoverished immigrant neighborhood of Marseille, where fouls and insults are met with instant retribution.
Perhaps he could never shake off that you-or-me mentality.
"You can take the man out of the rough neighborhood, but you can't take the rough neighborhood out of the man," striker Thierry Henry said Sunday.
At this year's World Cup, where Zidane sat out one match for getting two yellow cards in the first round, he sent a message to his teammates. In a rare television interview, he said, "We die together."
They were ready to go as far as they could for him, yet he punished them.
"He'll carry that weight for a long time," France coach Raymond Domenech said of Zidane's latest red card.
Zidane nearly won the match with a late header after giving France an early lead with a penalty, taking two steps forward to slowly chip the ball into the air while goalkeeper Gianluigi Buffon dived to his right.
It was his third goal of the tournament and sixth in the last 10 major tournament matches. He scored three at the 2004 European Championship.
Zidane's teammates had all wanted to help him to one last trophy. Failing that, they refused to kick him when he was down.
"For all that Zidane has done for the national team, you have to say 'Thank you and well done,'" said striker David Trezeguet, the only player to miss his penalty kick in the shootout.