Indian fast bowler Sreesanth, right, is escorted in a police vehicle on his way to court in New Delhi on Tuesday to face charges of alleged match-fixing. Agence France-Presse/Getty Images

For a long while, it really looked like the Indian Premier League season might come and go without any major setbacks. With no fallings-out between the league and its franchise owners this year, the only black eye had been the league's decision to bar Sri Lankan players from appearing in Chennai, India, as a result of tensions surrounding the treatment of Tamils in Sri Lanka.

That all changed last Thursday, 10 days from the end of the tournament, when the Delhi police dropped some bombshell news.

The police announced that it had arrested, among others, three current Rajasthan Royals players—fast bowler Sreesanth, off-spinner Ajit Chandila and left-arm spinner Ankeet Chavan—for alleged spot-fixing. Citing recordings of conversations between players and bookies, the police claimed that each of the players had conspired with illegal bookmakers to concede at least 14 runs in a given over of Rajasthan's matches this season against Pune Warriors on May 5 (Chandila), Kings XI Punjab on May 9 (Sreesanth) and Mumbai Indians on May 15 (Chavan).

Each alleged infraction, police said, took place in the bowler's second over, and each was supposed to be preceded by what it identified as a signal to the bookies: Putting towels in trousers, fiddling with wristbands, untucking shirts and so on, followed by time-wasting activities such as stretching and repositioning the field. Chandila, police also said, forgot about the signal, prompting the bookies to demand their money back.

Eleven alleged bookmakers were also arrested, among them Sreesanth's club-level teammate Jiju Janardhan, and former Rajasthan seam bowler Amit Singh. The trio of current players were immediately suspended by the IPL, saw their contracts suspended by the franchise, and taken into police custody. All three players' lawyers deny the claims and have accused the Delhi police of entrapment.

"Sreesanth has been falsely or mistakenly arrested," Sreesanth's lawyer, Deepak Prakash told reporters last week. He added that the Delhi police "have got some wrong information or mistakenly arrested him."

Spot-fixing, where specific elements of a game are rigged, is popular with the illegal gambling fraternity because it's relatively easy to pull off. It only needs the participation of a single player, and a single fixed over is almost impossible to detect: 14-run overs are so common in Twenty20 cricket that the recent incidents would ordinarily have attracted no attention.

That makes it easy to think of spot-fixing as a relatively minor crime, one that just affects a few balls of a game. Indeed, Rajasthan went on to win the first two of the games in question. Only in Rajasthan's game against Mumbai could any of the alleged fixes have had a direct effect on the outcome.

But the potential consequences actually reach much further. Beyond the result, it can also affect the net run rate—important in T20—and more importantly, has been shown in the past to be tied to organized crime.

In this case, police said, the players were allegedly offered between $36,000 and $109,000 for each fixed over they bowled. Delhi police commissioner Neeraj Kumar added that they would stand to earn "crores" of rupees from a single fix, with a crore roughly equivalent to $180,000.

Still, during its first two years, the league wasn't monitored by the International Cricket Council's Anti-Corruption and Security Unit, set up in 2000 to educate players, monitor and investigate alleged fixing incidents. That was despite a warning from the inaugural head of that body, former commissioner of London's Metropolitan Police Paul Condon, that T20 leagues such as the IPL provided the biggest corruption threat in decades because of its high profile and popularity with gamblers.

Instead, the league employed a private security firm for those two seasons. Condon said that there was no evidence of fixing in those seasons. But with no monitoring, it was impossible to tell. N Srinivasan, president of the Board of Control for Cricket in India, which runs the IPL, has also said publicly that the arrests don't affect the credibility of the IPL but that the door was left open for suspect characters to start hanging around the game during the league's first two years.

"There have been some bad eggs, through the history there have been some bad eggs here and there but that doesn't mean that whole tournament is bad, everything is fixed. I don't subscribe to that at all," Srinivasan said in an interview with CNN last week.

One other issue is that the ACSU is hampered by limited budgets, pressure from IPL team owners and by its lack of investigative powers. Every major fixing probe in cricket has been initiated by either the police or the media. The most recent arrests came about because police were investigating the suspected involvement of the Mumbai underworld in cricket corruption. The only other previous fixing allegations in the IPL, which resulted in five lesser domestic players being banned, came about as a result of a sting operation by an Indian television channel.

The BCCI set up its own anticorruption unit last year, but it had nothing to do with the arrests. Its head, Ravi Sawani, said he would run his own investigation into the allegations. The BCCI has also said that it will regulate player agents, and assigned an individual ASCU officer to each of the four teams to qualify for the final stages of the league.

Cricket knows it can't afford to be complacent about this kind of thing. Except even jail sentences for convicted fixers—like those received by the English domestic player Mervyn Westfield and the Pakistani international trio of Asif Butt, Mohammad Asif and Mohammad Amir—don't appear to have done the trick. Which might mean that the sport's own authorities need to up the investigative ante, work more closely with the police and ensure that in the future cricket can identify its own problems.

"If somebody through the process is found guilty, then we will act," Srinivasan said at a news conference. "We will act very strongly."

—Richard Lord writes about cricket for The Wall Street Journal.