ROME (AP) -- Two years ago, a curious case landed on the desk of Italian prosecutor Roberto Di Martino in the town of Cremona.
Five players on the local third-division club Cremonese fell ill after a match against Paganese. One of the sick players crashed his car and club management reported the mysterious circumstances to police.
It turned out that Cremonese's goalkeeper had been bribed by match-fixers to make sure his team lost. Unable to recruit teammates to join in on the fix, he decided the next best option was to drug them. So he put tranquilizers in the team water bottles, according to police. Italian soccer officials banned him for five years.
EDITOR'S NOTE: This story is part of a six-month, multiformat AP examination of how organized crime is corrupting soccer through match-fixing, running over four days this week.
"It sounds like a fairy tale or a novel. It's absolute craziness, something unbelievable -- but it's all true," Di Martino said in an interview with The Associated Press.
"At the start it seemed like it was just for a few matches, then we figured out that it was pretty much a global system."
The investigation has thrust the 62-year-old Di Martino into the heart of one of the biggest match-fixing cases ever revealed: more than 210,000 tapped phone calls, more than 150 suspects under investigation, hundreds of matches analyzed in all four of Italy's professional divisions, dozens of people arrested and scores more wanted all over the world.
Among those arrested in "Operation Last Bet" were former Lazio captain and Italy national team forward Giuseppe Signori and former Atalanta captain Cristiano Doni.
Prosecutors in Naples and Bari have opened related investigations. Di Martino feels like he's hardly made a dent and is overwhelmed, especially since he has to also handle the routine daily work in his small office that has nothing to do with rigged soccer matches.
"If I were working full time on this I could find out more, but I'm the leader of an office that also handles administrative matters. I lose more time for administrative matters than for trials," he said.
Di Martino isn't alone. Prosecutors in Germany have uncovered about 340 games that they believe were fixed, but they can investigate only half of them because they don't have enough staff, a German investigator told AP on condition of anonymity because he was not authorized to discuss investigations with the news media.
Even if prosecutors can catch players involved in fixing matches, hunting down the international money trail has proved far more elusive.
"These guys operate at a very global level. The police have no idea how to operate at a global level like crime does. They can do what they like, travel as they like," said Chris Eaton, the former head of security at soccer's governing body FIFA and now director of integrity at the International Centre for Sport Security, a Qatar-backed group funding research into match-fixing and ways to fight it.
When Eaton was at FIFA, the former detective and his handful of investigators opted to interview suspects and pursue cases across the world. Because he had few evidence-gathering powers and little support from national law enforcement agencies, FIFA had limited success.
Ralf Mutschke, a former Interpol manager who succeeded Eaton last year, has switched tactics, focusing more on education and prevention. National agencies investigate match-fixing, with liaison support from FIFA's 209 members associations.
"Everyone has a role to play," Interpol Secretary-General Ronald Noble told the AP. "There has to be prosecution. There has to be prevention. ... There's got to be internal work from FIFA. There's got to be work from the legal betting agencies. It's a huge problem, a huge problem."
In Italy, match-fixing by itself is not considered a serious crime.
"It's considered a minor type of fraud -- sports fraud -- which is penalized with sentences of a maximum of two years," Di Martino said.
Furthermore, most sentences up to two years in Italy are routinely suspended. And many accused match-fixers face investigation and disciplinary action by sports federations before criminal prosecutions proceed.
While those involved in Operation Last Bet have not yet gone to a criminal trial, Italian football federation prosecutor Stefano Palazzi has already handed out numerous bans from soccer and punished teams by dropping them in the league standings.
Doni was banned from football for 5 1/2 years for allegedly betting on fixed games and Atalanta has been docked points -- both last season and this season. Signori, allegedly a key link between money runners in eastern Europe and players who fixed matches, was banned for five years, even though he's retired.
In all, 13 clubs in Italy's top two divisions have been punished in the standings this season with point deductions.
Antonio Conte, the coach of defending Serie A champion Juventus, completed in December a four-month ban for failing to report fixing when he guided Siena two seasons ago.
In other countries as well, match-fixers go free because there aren't laws on the books or it is not considered a serious crime.
In November, three players in Switzerland were acquitted in a match-fixing case, and the country's Football Association said the criminal code needs to be updated. The judge ruled that an online betting scam did not yield a victim.
Di Martino was drawn into the case when it was still believed to be the more serious crime of a drugging incident, thus enabling him to use investigative practices that might not have been employed for match-fixing.
"Criminal association allows phone taps, but it's not like you automatically have proof of criminal association, so it's nearly impossible to do phone taps unless you have much, much bigger reasons to," he said.
Di Martino previously worked on terrorism and organized crime cases when he was based in Brescia until 2008.
"It was a fortunate combination that led to all this, and it's unlikely to happen again," he said. "Once this trial is held, if they don't change the rules of the game, it's unlikely you'll see trials like this again."
For prosecutors, there are several ways to prove match-fixing -- the best being confessions by players and fixers alike in the same case. That happened in Croatia in 2010, when local police, tipped off by prosecutors in Bochum, Germany, put a wiretap on fixer Vinko Saka's phone and started reeling in the co-conspirators. Fifteen players, coaches and officials went on trial for match-fixing there, and the police wiretaps were so extensive that several of them pleaded guilty. Saka himself got a plea deal from prosecutors that also required him to testify about match-fixing in Italy.
The Bochum case, which led to investigations in other European countries, was built on wiretaps requested on convicted match-fixer Ante Sapina when he was released from prison following a German refereeing scandal that broke in 2005.
Turkish police also used extensive wiretaps in their case in 2012 charging 93 people, including senior soccer officials, with match-fixing.
Prosecutors can also build evidence from money transfers.
Sometimes players report to police that they have been approached by fixers, and the subsequent investigation uncovers match-fixing.
In 2011, Serie B player Simone Farina was offered 200,000 euros ($260,000) to influence the outcome of an Italian Cup match between Cesena and his club, Gubbio. Farina refused and reported the incident to the police. He was widely applauded, and FIFA made him an ambassador in its fight against fixing, but the whistleblower had trouble finding a club and retired before moving to England's Aston Villa in a coaching role.
"My vision is that one day, the decision I made will not be treated as the exception, but rather the rule," Farina said in a recent speech.
The confessions of convicted Singaporean fixer Wilson Perumal also provided valuable source material after his arrest in Finland.
On-field behavior -- blatant referee or player mistakes -- can really only be used as corroborating evidence, because there can be legitimate reasons for poor performance.
However, there might be grounds to investigate if all the scoring in one game is due to questionable calls by a referee, or if online betting monitors notice unusual in-game spikes in wagering, or if the game's unexpected result keeps a team from being demoted to a lower league.
The most successful match-fixing is opaque -- a win by a team that is expected to win, a loss by a team expected to lose, an unusual outcome in an exhibition or "friendly" match that doesn't count in the standings.
Sophisticated match-fixers now use scores of smaller bets on a fixed game instead of one large wager, and they often wait until the last minute to lock in the odds before betting companies can notice shifts.
Widespread soccer scandals are not new in Italy. Court cases are still going on from a 2006 match-fixing inquiry dubbed "Calciopoli," which involved clubs putting pressure on referees and led to 28-time Italian champion Juventus' relegation to the less-prestigious Serie B, as well as penalties for a handful of other clubs.
The last major betting scandal in Italy was in 1980, when there were also numerous arrests and bans for club officials and top players, including Paolo Rossi, who returned to lead Italy to the 1982 World Cup title.
Di Martino is convinced that match-fixing continues in Italy, despite his investigation.
"I'm sure it still goes on," he said. "I strongly doubt it has stopped. ... I hope this inquiry makes an impact, and just for that I'm trying to keep it going."
AP Sports Writer John Leicester in Paris and Assistant Europe Editor Sheila Norman-Culp in London contributed to this report. Dunbar reported from Geneva.