PARIS (AP) -- When police arrested Wilson Raj Perumal in Finland, it didn't take long for him to realize that his criminal buddies had ratted him out.
He's been exacting revenge ever since -- by ratting on them, too.
Since his arrest in 2011, Perumal has been talking to police, prosecutors and journalists about the shadowy world of fixing soccer matches, in which he was an active participant, and the millions of dollars that can be made in betting on them.
EDITOR'S NOTE: This story is part of a months-long, multiformat AP examination of how organized crime is corrupting soccer through match-fixing, running over four days this week.
The Singaporean was convicted in the Lapland District Court of bribing players in the Finnish league, forgery and trying to flee from officials guarding him, and was sentenced to two years in prison.
Perumal told police that he could be in danger for betraying his former colleagues. But Perumal also reasoned that by fingering him to the Finns, his associates broke the cardinal rule of criminals not cooperating with law enforcement.
"It's not in my nature to sing like a canary," he wrote in a letter from jail. "If I had been arrested under normal circumstances, I would have been back in Singapore to serve my time as a guest of the state with my mouth tightly shut."
European investigators and prosecutors say Perumal has provided an invaluable window into the realm of match-rigging, which is corroding the world's most popular sport. They say he has revealed who organizes some of the fixing in football, as the sport is known in most countries, and how money is made wagering on outcomes prearranged with players, referees and officials who have been bribed or threatened.
"He's not the only operating match-fixer of this style or this size in the world, but he's the first to be really captured in the way he was and now to cooperate the way he is," said Chris Eaton, who was head of security of FIFA, soccer's governing body, at the time of Perumal's arrest.
"He put two and two together and realized he'd been traitored," Eaton said in an interview with The Associated Press. "It took several days before he decided that it was in his best interests to cooperate."
Police from Italy investigating dozens of fixed Italian games and a prosecutor looking into 340 suspect games elsewhere in Europe both traveled to Finland to question Perumal as a witness.
One investigator on those trips told the AP that Perumal provided "very good interviews," that he is still cooperating even after his release from prison in Finland, and that evidence he provided has checked out.
Another investigator told AP that Perumal alerted authorities to two fixes in progress -- the matches, the referees -- and that his information was "100 percent" right in both cases. That investigator called Perumal "a massive help."
Both investigators spoke on condition of anonymity because they were not authorized to discuss their work publicly. Perumal declined an AP request for an interview.
In court filings, Italian prosecutors described Perumal as their "primary source of evidence" on Tan Seet Eng, also known as Dan Tan, a Singaporean they allege is the leader of the syndicate that fixed matches in Italy. Perumal detailed to authorities how the syndicate is structured, how it places bets, and how it moves bribe-money around the world, they said.
Italian prosecutors have issued an arrest warrant for Tan and listed him as the No. 1 suspect in their match-fixing investigation. Prosecutor Roberto Di Martino told the AP there are about 150 people under investigation, including Tan, but none of them has been indicted.
AP could not contact Tan in Singapore. Five phone numbers identified as his by Italian prosecutors were disconnected, and no one answered the door at an apartment the Italians listed as his address.
Perumal told Finnish police that the syndicate has six shareholders -- including himself -- from Singapore, Croatia, Bulgaria, Slovenia and Hungary, and he said they divide up income from gambling on fixed matches. The syndicate places bets mainly in China, Perumal said, according to a transcript of his May 18, 2011, police interview obtained by the AP.
He said the group fixed "tens of matches around the world" -- in Europe, Africa, the Middle East and the Americas -- from 2008 to 2010. He estimated the group's total profits after expenses at "several millions of euros, maybe 5-6 million."
"Perumal is key, because he provides a view into how it all fit together," Di Martino told the AP.
Investigators said Perumal has a long history as a match-fixer and a broad array of contacts in soccer. He boasted in a letter from prison: "I can pick up the phone and call from Afghanistan to Zimbabwe."
When arrested, he had numbers stored in his phone for people in 34 countries. He carried a business card with a FIFA logo that described him as "executive manager."
Perumal wrote from prison that he started fixing matches in Asia in the early 1990s.
"I grew up in a region where football betting and match-fixing was a way of life. Gradually I developed the ability and the expertise to execute the job myself," he said.
He claimed to have paid off players in Syria and Africa and spoke of fixes in the U.S. and in Bahrain, as well as games involving teams from North Korea, Kuwait, Zambia, Bolivia, Venezuela and Togo. Zimbabwe linked him to widespread corruption and fixes involving its players and soccer association.
Perumal also is suspected of rigging games involving South Africa before it hosted the 2010 World Cup. FIFA determined that Perumal's company, Football4U, was a front for his betting syndicate and infiltrated the South African Football Association.
In Finland, Perumal told police how he distributed bundles of cash -- tens of thousands of dollars at a time -- to corrupt Finnish league players, including a 56,000-euro bribe handed over in a stadium lavatory in 2010.
In a prison letter, he lamented that "all corrupt players and officials are like whores who will walk with the highest bidder. There is no loyalty in this business."
But he felt no guilt about his role.
"I have had players thanking me for giving them this opportunity and telling me how much this money will change their lives," he wrote. "The only people who get affected are the illegal bookmakers, and they dissolve their losses in the massive turnover of profits."
Perumal had been in and out of jail repeatedly in Singapore. In 2010, he was given a five-year sentence for injuring a police officer. He appealed but then skipped town. Singapore police spokeswoman Chu Guat Chiew told the AP that Perumal is still wanted in Singapore.
In his prison letters, Perumal said he lived unnoticed in London while on the run, jogging daily around Wembley Stadium and attending Premier League matches on weekends. The handwritten prison letters were sent via Perumal's lawyer to a journalist, Zaihan Mohamed Yusof of the New Paper in Singapore.
If not for peculiar circumstances in Finland, Perumal might never have talked.
His arrest came on a tip from an informant, also Singaporean, who walked into a police station in Rovaniemi in northern Finland in February 2011 and told the duty officer that Perumal was in the country on a counterfeit passport and staying at the Scandic hotel, Finnish police told investigators. But the informant gave police the wrong room number, so they detained the wrong man, who was later released.
Once armed with the correct room number, police tracked down Perumal and put him under surveillance to be sure that they had the right man, said Eaton, the ex-FIFA security chief who is now director of integrity at the International Centre for Sport Security, a Qatar-backed group funding research into match-fixing.
Finnish police followed Perumal to a game and saw him in heated discussion with a player. That piqued their curiosity and prompted them to contact soccer officials. They, in turn, got word to Eaton at FIFA, who already had Perumal on his radar and immediately recognized the significance of the Finnish catch.
"It was like a bell went off, an alarm went off, in my office," Eaton told the AP. If the police hadn't tailed Perumal and had just picked him up and sent him home for traveling on a fake passport, they might never have realized he was fixing matches and he might never have decided to cooperate, Eaton said.
"It would have been virtually a blip instead of the explosion it really was," Eaton said.
Before his arrest, Perumal had been gambling heavily, built up debts and bilked his syndicate by pocketing money meant to be used to fix matches, Eaton added. He said Perumal also had become too high-profile for Tan, who is believed to be in Singapore.
Perumal "was on Facebook. He was on LinkedIn. He was on Twitter," Eaton said. "Perumal's attitude was, 'This makes me more valuable, more known by players, more known by the people I want to corrupt and influence.' Dan Tan wanted him to be more discreet."
In a prison letter, Perumal alleged that the tip to Finnish police was an effort by his associates "to get rid of me."
"I knew I was set up the moment they stopped me," Perumal wrote.
"Seeking police assistance is a violation of code No. 1 in any criminal business. Dan Tan broke this code and stirred the hornets' nest. And now he has to face the consequences," Perumal wrote in another letter. "I hold the key to the Pandora's box and I will not hesitate to unlock it."
Investigators say Perumal's decision to cooperate also was motivated by self-interest. As long as he remains useful to authorities in Europe, he delays the day he might be sent back to Singapore, where he faces a prison term and possibly vengeful former associates.
"He'd be in prison for five years and perhaps he wouldn't come out of that prison," Eaton said. "He progressively started giving information. Not at once, not in some great blurting splurge. He gave enough each time to ensure that he wasn't extradited, that he wasn't sent back to Singapore, to a point where he gave enough that they are now using him in other investigations.
"Progressively, he's realized, 'The only way out for me is to become an informant and to cooperate,'" Eaton added. "But I still don't believe he's given anywhere near 100 percent of the information."
After serving half of his two-year jail sentence in Finland, Perumal was sent to Hungary, which had a European arrest warrant out for him, said Detective Chief Inspector Jukka Lakkala of the Finnish Bureau of Investigation.
Eaton said Perumal served as a "controlled informant" in Hungary, living in a safe house under police watch.
"And no doubt he'll be in Italy, too," Eaton added.
In declining the AP interview request, Perumal replied in an email that he did not want "to provide any more details."
"My life is now settled," he said, adding that he prefers that it "remains that way."
Matti Huuhtanen in Helsinki, Pablo Gorondi in Budapest and AP Sports Writer Andrew Dampf in Rome contributed to this story.