IN 2008 Lou Vincent, a former New Zealand international cricketer, was playing in a now-defunct Indian Twenty20 cricket league. A man claiming to represent a cricket-bat manufacturer invited him to a hotel room. But instead of being shown bats he was offered a prostitute and a wad of cash.

He left, and now says he told his captain, Chris Cairns, what had happened—and that, rather than encouraging him to report what was clearly a match-fixer’s opening gambit, Mr Cairns tried to recruit him to fix on his behalf instead. (Mr Cairns denies this, and won £90,000, or $122,000, in libel damages after suing a cricket official for accusing him of match-fixing.) In 2013 rumours and odd patterns of gambling made the authorities suspect Mr Vincent, who had moved to England. The following year he admitted to 18 charges of fixing and was banned from cricket for life.

What makes Mr Vincent’s story unusual is that he was caught. Those responsible for tackling match-fixing believe it is more prevalent than ever. Yet it mostly remains undiscovered. Each new case makes big news, like that of Khalid Latif, a Pakistani cricketer who had played in international matches. On September 20th the Pakistani Cricket Board banned him from the game for five years for “spot-fixing”—taking money to play to order for part of a match, rather than determine the overall outcome—after an investigation into corruption in a national league.

In a recent survey of more than 600 European athletes in 13 sports by Vassilis Barkoukis of Aristotle University in Thessaloniki, a third said they believed that they had played in fixed matches. A fifth said they were aware of a fixed match involving their team in the previous year. Sportradar, a firm that uses statistical techniques to spot dodgy bets, identified 1,006 contests that it thinks were probably manipulated during 2015 and 2016, and 451 in the first eight months of 2017, the highest rate since it began tracking sports betting in 2008 (its database has also grown).

Winning isn’t everything…

About four matches in 1,000 raise red flags in Sportradar’s system. But around one in 100 are probably fixed, says Ian Smith, the first integrity commissioner for “eSports”—competitive video-gaming (see article). Regulators are slowly turning to analyses of betting patterns as evidence. Sportradar’s reports have been used successfully in just 24 prosecutions since 2013. But 13 sports have signed up in recent years to receive its reports. In a landmark case last year the Albanian football champions, KS Skenderbeu, were banned from the Champions League based solely on Sportradar’s betting analyses.

The growth in match-fixing has been fuelled by the vast amount wagered on sport—around $2 trillion a year, according to the International Centre for Sport Security (ICSS), a think-tank. It estimates that criminal groups launder $140bn by match-fixing and illegal betting each year.

Corruption is most common at the second-tier level: in small football leagues, domestic cricket tournaments and so on. This is the sweet spot where enough money is staked for corruptors to clean up—and players earn little enough to be easily tempted. In tennis, for example, only the top 160 men and 150 women make enough in prize money to cover their costs. “The whole sport is structured in a way that begs corruption. There are too many tournaments and too many players,” says Mr Smith. The problem is so notorious that tennis players are routinely accused on social media of throwing matches.

Players are recruited by fixers in a manner that Ronnie Flanagan, the chairman of the International Cricket Council’s anti-corruption unit, describes as “grooming”. Nchimunya Mweetwa, a Zambian footballer who was signed to a Finnish club in 2007 and found guilty of fixing in 2011, said that men who he thought were football agents befriended him, gave him gifts and only later threatened violence if he did not fix for them. Another device is the “honey trap”—a woman paid to strike up an acquaintance with a player and introduce him to fixers, or even to have an affair with him, meaning photographs can be taken and used as blackmail if he rebuffs them.

Even in team sports, fixers usually need to enlist just a single athlete. Betting activity is centred on a few outcomes. In football, for example, 95% of the total staked goes on the match result, the margin of victory and the number of goals. A fixer who knows that a player will be sent off, and approximately when, can use this knowledge to predict the way odds will move. Placing bets both before and after makes it possible to lock in a profit.

Players can manipulate betting markets in other ways. A bowler might agree to bowl no-balls at a particular point in a cricket match, or a tennis player to lose a particular game. Such things often happen by chance, making them easy to conceal and allowing players to rationalise their actions as victimless crimes, rather than frauds against fans, punters and their unsuspecting team-mates. A one-off fix of a single game within a tennis match can be “virtually impossible” to spot, says Mark Harrison of the Tennis Integrity Unit (TIU), the sport’s anti-corruption body. But a player who has started fixing can be blackmailed to continue, and suspicious patterns may emerge.

Making matters worse is a betting-industry “arms race”, says Tom Mace from Sportradar, with bookmakers taking bets on ever more matches, including at semi-professional, amateur and youth level. It is also hard to persuade players to be clean when there are so many questions about the probity of sports administrators, for example over the choice of World Cup and Olympics hosts. And teams’ financial interests are more enmeshed with bookmakers than they used to be. Until 2002 no Premier League football club had a bookmaker as a shirt sponsor; now nine do.

…It’s the only thing

Most sports spend a minuscule fraction of revenue on anti-corruption measures such as educating players and officials about fixers’ methods, or on monitoring betting patterns and sending officials to tournaments. The TIU had just five staff as recently as last year; it now has 11—still not enough for a presence at every professional event. Its budget for 2017 is $3.2m. It should be at least $10m, Mr Smith believes. Tennis authorities do not always realise how incriminating strange betting patterns can be, says Dan Weston, a sports and betting analyst. The TIU does not employ a full-time betting analyst.

Many countries have no specific law against match-fixing. In 2012 three Swiss footballers were acquitted largely because a national law against sporting fraud had yet to be passed. At worst a perpetrator will be fined a few thousand dollars or, occasionally, sent to prison for a few months. One notorious Singaporean match-fixer, Wilson Raj Perumal, who has confessed to fixing dozens of matches, had contact with officials and players in at least 38 countries (including Mr Mweetwa in Finland). He was convicted several times, apparently without much deterrent effect. A proposed Convention on the Manipulation of Sports Competitions would set anti-fixing standards across the 47 members of the Council of Europe. But it risks being blocked by just one, Malta, which worries about the impact on its remote-gambling industry.

Worldwide, only about 15% of sports betting is legal, says the ICSS. It is illegal in most American states, and in many Asian countries, including China (except for a state monopoly) and India (except for on horse-racing). Illegality makes it harder to reveal fixing by following the money. “If you create a black market you make everything twice as hard—monitoring, regulating, licensing, customer protection,” says Alex Inglot from Sportradar.

Growing interest in women’s cricket and football will result in more match-fixing, warns Mr Barkoukis. The Women’s Cricket World Cup final, in July, had £78m traded on Betfair, a record for any women’s event with the sports-betting exchange, and 860% more than the previous final, in 2013. More televised games and few players earning big sums will make women cricketers a target, says Clare Connor, the director of England Women’s Cricket.

Regulators will need to up their game. One woman cricketer recalls an anti-fixing talk at the Women’s World Cup in 2014, which had clearly been copied wholesale from one for male players. “He warned us that attractive men might approach us in the hotel bar and ask for a drink, with the aim of trying to inveigle an invitation to a player’s bedroom,” she says. “If that happened we were supposed to excuse ourselves, go to the toilet, look in the mirror and ask ourselves: ‘Am I really that good-looking?’” No fixer would have such a poor grasp of human nature.