ISTANBUL (AP) -- Turkey loves both soccer and strong men, so it's no surprise that Aziz Yildirim is a household name.
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.
EDITOR'S NOTE: This story is part of a six-month, multiformat AP examination of how organized crime is corrupting soccer through match-fixing.
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.