MADRID (AP) — Spanish authorities have detained 34 people, including six tennis players, involved in a tennis match-fixing network that made more than half-a-million dollars from lower-tier tournaments in Spain and Portugal.

Police said Thursday that Operation Futures probed several Futures and Challenger tournaments in Iberia for the past several months and found evidence that results were rigged.

The tennis players were not identified, but authorities said they were ranked between 800 and 1,200 in the world. Their Spanish rankings ranged between 30 and 300.

Police said they found evidence of match-fixing attempts in 17 men's tournaments in five cities, including Madrid, Seville and Porto.

Authorities said the two alleged leaders of the network were among those detained across 12 Spanish cities. The leaders were based in Seville and La Coruna. All those detained were Spaniards and are expected to remain free pending trial.

If convicted of corruption in sports, they could face prison sentences of up to four years.

The investigation began after a tip given by a player to the Tennis Integrity Unit, the sport's anti-corruption body.

"Investigation of corruption allegations by law enforcement agencies takes precedence over tennis disciplinary action," the body said in an email. "The TIU will continue to work co-operatively with (Spanish police) and offer its full support and access to resources."

Authorities took the case forward after noticing an unusual amount of online bets related to the suspected tournaments.

The network allegedly used instant-messaging groups and social media to attract online betters who would pay for the information about rigged results.

The players who accepted participating in the scheme would receive about $1,000 for each match. In some cases, they were asked to lose specific points or games.

The network's earnings in some of the tournaments surpassed $10,000.

The Challenger tournaments are second-tier events organized by the ATP, while the Futures are single-week competitions organized by the International Tennis Federation offering either $10,000 or $25,000 in prize money.

There were nearly 39 Futures tournaments in Spain this season, and more than 10 in Portugal. Spain hosted Challenger events in Sevilla and Segovia.

_

Tales Azzoni on Twitter: http://twitter.com/tazzoni