A civil engineer, Yildirim made a fortune in military contracts with the government and NATO before turning his attention to Istanbul's Fenerbahce soccer club, a perennial title contender with a vocal fan base nicknamed "the Republic of Fenerbahce."
As chairman since 1998, Yildirim built up not only the local soccer club, but also its clubs in basketball, volleyball and table tennis. He renovated the stadium, increasing it to 52,000 seats and installing outdoor heating.
Under his leadership, Fenerbahce became one of the world's top 20 wealthiest soccer clubs and was the pride of Turkey as it ventured often into Europe's lucrative Champions League, which pits the top finishers in each of Europe's major national leagues. The blustery, volatile Yildirim was as well-known as the prime minister.
In 2012, however, he got attention for all the wrong reasons.
The 60-year-old tycoon was convicted in July by Istanbul's 16th Heavy Penal Court of "forming and leading a criminal gang" that rigged four games and offered payments to players or rival club officials to fix three others
-- all so Fenerbahce could stay in the Champions League, a benefit the club estimated to be worth $58.5 million a year. He is appealing his conviction, maintaining his innocence.
Yildirim's case is another sign that soccer -- the world's most popular sport
-- is increasingly tainted by a multibillion-dollar scourge of match-fixing. Investigations in dozens of countries in 2012 have involved hundreds of players and officials, revealing the extent of the problem that threatens to undermine the integrity of the game.
Matches can be rigged so that criminal gambling rings and others in the know can make money off bets. But sometimes, the rigging is done to keep a team in a more prestigious league, where it can earn big revenue.
Fenerbahce was founded in 1907. It has 18 national league titles, the same as Istanbul rival Galatasaray, and a fan base that expects more.
The name "Fenerbahce" means "lighthouse garden" in Turkish. Many of its fans take the 30-minute ferry ride from the European side of Istanbul across the breezy Marmara Sea to Kadikoy, the bustling district on the city's Asian side where Fenerbahce plays its home games.
Fans wearing the club's blue-and-yellow stripes pack Sukru Saracoglu Stadium, which sits along a boulevard lined with shops, bars and restaurants.
In two recent seasons, the team had lost the league championship in its final few games, an outcome the prosecutors' indictment said Yildirim wanted to avoid repeating.
Faced with that pressure, in spring 2011, Fenerbahce won 16 of its last 17 games to come from a distant third place and stay in the Champions League.
"Whatever you do in a season, if you don't qualify for Europe (Champions League), it doesn't mean anything," explained Turkish lawyer Emin Ozkurt, who has represented Fenerbahce in other cases.
Yildirim was put on trial last spring along with 92 other officials, players and coaches.
Turkish police had 1,028 wiretaps relating to the 13 games in question, 103 of them tied to Yildirim. He was charged with match-fixing and accused of trying to get favorable referees assigned to his team's games. Prosecutors also said that the transfer fees he paid to some rival clubs and players were actually payoffs for fixing games.
A 2012 global study on match-fixing conducted jointly by four international research institutions noted that "chairman-to-chairman" fixing is quite common in the Balkans, eastern Europe and Russia, especially when a win is very important to one club and less so for a rival.
"The risk of matches being rigged in this way increases as the end of the season approaches, if a team is still in contention for a promotion or a victory in a championship or is trying to avoid relegation," the study said. "Club chairmen ... not only often know each other personally, but above all, understand each other because they all have the same aims and constraints."
Club officials also know which players are less scrupulous or in financial trouble and can be easily pressured into throwing a game. The report said chairman-to-chairman match-fixing "can even assume systemic proportions" in which favors done for one team one year are paid back by rigging more games the next season.
The Fenerbahce case was not Turkey's first brush with match-fixing. The prosecutors' indictment noted that since 1980, Turkish football has attracted a host of criminal gangs and mafia dons.
Prosecutors said the wiretaps in the latest scandal revealed an elaborate code based on farming and construction terms that Yildirim and other Fenerbahce officials used to talk about match-fixing.
"Buildings under construction" referred to games in the process of being fixed. "Goats in the field" referred to players, "crops being watered" were match-fixing payments, and "plowing, planting and sowing" were efforts to fix games. The agricultural terms used by the city-dwelling soccer officials often did not correspond with the actual farming seasons, prosecutors noted.
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In court, Yildirim was confronted with what prosecutors called a transfer fee of $100,000 paid by Fenerbahce for midfielder Gokdeniz Karadeniz, who ended up never playing for the team. He insisted the payment was legitimate, and said investigators hounded his team so much that players such as Karadeniz were too upset to play.
"Players (who) transferred with great hopes and without the slightest irregularity were detained, put under pressure and ... left the club without wearing the team uniform once," Yildirim testified.
Prosecutors say Yildirim aides spoke with the manager of Nigerian striker Emanuel Emenike to make sure he did not play in a spring 2011 game against Fenerbahce. Emenike then transferred to Fenerbahce for an undisclosed fee but never played for the team and later transferred to Russia. Emenike was charged in the match-fixing scandal but since he is out of the country his case was separated from the others, and is ongoing.
Prosecutors said another Fenerbahce official gave $129,300 to Ibrahim Akin, a player for a rival team, to throw a game. Akin was convicted of match-fixing and sentenced to 18 months in prison; he is appealing.
They also said Fenerbahce aide Abdullah Basak was given a Mini Cooper as a reward for meeting with officials and players of other clubs to fix games. Basak's sentence of 15 months in prison for membership in a "criminal gang" was commuted. He was convicted and sentenced to a further 2 1/2 years for match-fixing, which he is appealing.
Yildirim also was accused of asking former Turkish Football Federation head Mahmut Ozgener about the referees who would handle Fenerbahce games, seeking those who would favor his team.
Yildirim conceded that wiretaps show him asking referee chief Oguz Sarvan to talk to the referee overseeing the next Fenerbahce game, but said it was only because the man was known to be a devoted follower of the Besiktas team.
"The conversations are ordinary, the type of conversation any club director would make. There is no request for favoritism but a request for an unbiased referee," Yildirim said.
Yildirim denied any wrongdoing and mocked the allegations against him, saying police initially declared irregularities in 19 games but mentioned only 13 in the indictment.
"Six games vaporized?" he asked.
Yildirim called the trial a plot "to block Fenerbahce and prevent its rise."
"It is clear as day that this is an operation against the Fenerbahce Sports Club and against Aziz Yildirim," he testified. "A group wanting to take over Turkish sports organized this operation."
Yildirim was convicted and sentenced to six years and three months in prison. He spent a year behind bars, but was released pending an appeal; a decision is expected this spring. Fenerbahce officials refused requests to interview Yildirim.
If the conviction and sentence are upheld, he will return to prison and be forced to step down as Fenerbahce chairman.
Three other Fenerbahce officials and officials from five other teams also were found guilty.
Fenerbahce was barred from last season's Champions League as a result of the investigation, but UEFA says the team is eligible to participate in next season's competition, pending a final ruling by the disciplinary board of UEFA, Europe's soccer body.
Fenerbahce, claiming it was treated unfairly by UEFA and the Turkish Football Federation, appealed to the international Court of Arbitration for Sport, seeking $58.5 million in damages. It later dropped the case.
Meanwhile, a change of regime occurred in the Turkish Football Federation as its chief resigned. Under new leadership, the organization declared that none of the match-fixing affected any matches and cleared all of the clubs mentioned in the indictment.
It banned two players, for alleged efforts to throw a game that Fenerbahce won 4-2.
Few in Turkey believe match-fixing is limited to that, and few believe it has ended. Turkish sports commentator Bagis Erten notes that rigging allegations have emerged every season for the past 40 years.
"The widespread belief in Turkey," he said, "is that at some time or another, each and every team has attempted to fix games."
Press; By SUZAN FRASER and NESHA STARCEVIC]
Fraser reported from
Ankara. Sheila Norman-Culp contributed to the story from London.
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