The probe is being led by authorities in Belgium, where the syndicate's suspected ringleader, an Armenian, is based. Belgian authorities say Grigor Sargsyan remains in custody in his home, monitored with an electronic bracelet.
Investigators say corrupted players bought off by the fixers knew Sargsyan as "Maestro." The massive scheme, organized via encrypted messaging and involving dozens of low-ranked players in small tournaments with little prize money, is believed to have spread tentacles to more than a half-dozen countries, including the United States. Belgian authorities say they've requested assistance from the FBI, as well as counterparts in Egypt, Slovakia, Bulgaria, the Netherlands and Germany.
This week's additional detentions were first reported Thursday by French sports daily L'Equipe. Officials didn't identify the players.
A Belgian investigator said five of the French players questioned so far have admitted to taking money from the syndicate to fix matches, and that one player believed to have fixed about two dozen matches confessed to police that he pocketed 30,000 euros ($ 34,000).
The probe has grown far bigger than Belgian authorities initially expected when they first swept up Sargsyan and others in a wave of arrests in June. He faces organized crime, match-fixing, money laundering and forgery charges.
The number of players suspected of involvement continues to grow. Belgian investigators, who have been pouring through phone records and other evidence, believe they have now identified 137 players suspected of fixing or attempted fixing. The syndicate allegedly paid 500 to 3,000 euros ($570 to $3,400) for fixed matches, sets or games. Police say the syndicate employed mules, people hired for a few dollars to place bets on fixed matches that were small enough to slip under the radar of gambling watchdogs.
The Belgian investigator said evidence collected so far suggests the syndicate knew other match-fixers in Spain but they weren't working together. Another investigator said several players who took money from the syndicate told the French police during questioning that they did so because prize monies at low-level tournaments are too small to pay their expenses.
Players told the police that they often saw the so-called Maestro at such tournaments, working to recruit other accomplices, and they described him as friendly and non-threatening, the investigator said.
So far, France has the biggest number of players questioned in the probe. The first four were named by investigators as Jules Okala, 21; Mick Lescure, 25; Yannick Thivant, 32; and Jerome Inzerillo, 29. None operated in the highest spheres of tennis. The career-best singles ranking of any of them was 354, reached by Inzerillo in 2012.
L'Equipe said it interviewed Inzerillo, accompanied by his lawyer, this week and that he told the newspaper that he had never been approached to fix a match.
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