(CNN) -- The beautiful game's ugly underside was exposed on Monday as one of Europe's senior crime fighters revealed hundreds of games are under investigation in what he described as "a sad day for European football."
Recent match-fixing scandals have centered on South Korea and South Africa, but Europol believes the highest levels of the game are now no longer safe with alleged corruption in two Champions League matches discovered, including one played in England, with 680 games in all being probed across the globe.
"This is the work of a suspected organized crime syndicate based in Asia and operated with criminal networks around Europe," Rob Wainwright, director of European law enforcement agency Europol, told reporters, following its 18-month probe.
"It is clear to us this is the biggest-ever investigation into suspected match-fixing in Europe. It has yielded major results which we think have uncovered a big problem for the integrity of football in Europe. We have uncovered an extensive criminal network."
A total of 380 games in Europe -- including World Cup and European Championship qualifiers -- have been deemed suspicious, with 425 match and club officials and criminals involved from 15 different countries.
The Champions League match in England, which took place in the "last three or four years", is now subject to "ongoing judicial proceedings."
It is estimated that €16 million ($21.7m) had been bet on matches by criminals, yielding an €8 million ($10.8m) profit, with the highest single bribe of €140,000 paid in Austria.
Wainwright will be writing to UEFA president Michel Platini to inform him of Europol's findings.
"I'm a committed football fan," added Europol's director of European law enforcement agency. "I'm encouraged by the serious way many football administrators are taking it and by the results of this investigation."
A further 300 matches outside of Europe, including in South America and Africa, are also under suspicion.
Most of the international level football matches involved were with national teams in Africa, Asia, Central and South America -- including two World Cup qualifiers in Africa and one in South America.
"CAF does not intend to take any action until receipt of the full disclosed information to be made available to us," said the Confederation of African Football (CAF) in a statement.
"Second, CAF will take action if the fixed matches fall within our jurisdiction at the continental level, and national when required."
Last month FIFA general secretary Jerome Valcke branded match-fixing a "disease" in an interview with CNN just weeks after lifetime bans were handed to 41 South Korean players found guilty of prearranging matches.
The president of the South African Football Association was suspended in December ahead of an investigation into match-fixing in the country prior to it hosting the 2010 World Cup.
Chris Eaton is a former head of security at football's global governing body FIFA who now works for Qatar-based sports security consultancy ICSS. He warned the threat facing soccer is greater than ever and that governments must do more to combat it.
"Sport is now under unprecedented attack from criminals and opportunists who conspire to manipulate the results of competitions around the world," Eaton said in a statement.
"What is apparent is that there is a clear absence of effective and collective government control on international gambling that deters match-fixers and organized criminals.
"It is this absence of governmental supervision at a global level where the real fight against match fixing and the manipulation of sport outcomes must now be fought."
The Europol investigation -- codenamed Operation VETO - is ongoing.