SAO PAULO, Brazil — Their faces hide behind scarves, gas masks and motorcycle helmets. TV images show them smashing cars, hurling bricks at police and setting tires ablaze on the streets of Sao Paulo and Rio de Janeiro. Brazilian politicians have claimed they are a national security threat.

But who really are these protesters who plan to run riot at the World Cup as soon as the inaugural game kicks off on June 12?

Brazil’s police allege the militants form an extremist group called the Black Bloc, and say they are watching its leaders. The local press has published exposes claiming that the Black Bloc is funded by foreigners intent on spoiling the nation’s moment of glory.

However, speaking to GlobalPost, a veteran of Brazil’s radical protest movement said the Black Bloc is not an organization at all. Rather, it’s a tactic of demonstrators who are leaderless, angry and determined to raise hell.

“It is the 10 percent of the demonstration that don’t run from police, who are not scared. Nobody owns it”