Authorities in Brazil have begun a crackdown on the notorious gang that has threatened a 'World Cup of terror' next summer.
Leaders of the First Capital Command drug cartel, known throughout Brazil as the PCC, were recorded by police wire taps threatening violence during the tournament.
The gang, the biggest criminal organisation in Brazil, is operated from within the country's prison system and membership numbers run into the thousands.
But police, who have been engaged in open warfare with the PCC for the last few years, say they do not believe it can carry out World Cup attacks.
The tournament kicks off in June with the opening game in the PCC's backyard of Sao Paolo, and thousands of fans are expected to descend on Brazil.
Police chief Fabiano Barbeiro, who has led a crackdown in the Sao Paolo suburb of Sao Bernardo, told Sky News: "We are prepared to avoid these sort of actions.
"We are monitoring them all the time and we sincerely believe it is not possible for them to attack.
"They don't practice violence for free, they have a purpose. The target is not common people, it is their opponents."
While we were with his team, they closed down an alleged PCC branch office which was taking in nearly a million pounds a month. Four people were arrested.
Laid out on a table at the police station were banks of seized mobile phones, piles of cash, accounting notes and bullets.
As a measure of the intensity of the fight between the police and the PCC, 100 police officers were murdered last year alone.
The PCC is controlled by Marcos Willians Herbas Camacho, known as Marcola, who has been in prison for murder since 1993. Police charts of his network list members by nicknames.
But former PCC drug trafficker Daniel Martins, who became a missionary after leaving prison, told Sky News he believed the group does not plan to attack the World Cup.
He said: "They would never do it because it would look bad for them. They are not stupid. They're not everything they're made out to be."
Prosecutors in Sao Paolo have conducted a three-year investigation into the PCC.
Chief prosecutor Marcio Sergio Christino told Sky News: "Yes, they have the capacity to attack the World Cup, but it is not in their interest to do that."
On Monday, the next round of tickets for World Cup matches go on sale. Fifa hopes more than three million will be sold.
