Admir Suljic, suspected of match-fixing in global football, has been taken into custody by Italian police.
The Slovenian was detained by Italian authorities after landing at Milan's Malpensa airport on a flight from Singapore on Thursday.
Suljic is wanted by judicial authorities in the Italian city of Cremona investigating a massive match-fixing case that has already brought the arrests of more than 50 people, with more than 150 under investigation.
Italian police said Suljic had been on the run since December 2011 and was considered a "key element" in the Last Bet operation.
Police said he spent significant time in Singapore in close contact with the alleged fixing organisation's chiefs.
Earlier on Thursday, speaking at a match-fixing conference in neighbouring Malaysia, Ronald Noble, secretary-general of Interpol, said that Singaporean police had notified authorities in Italy that a suspected match-fixer was flying to Milan.
Singapore has come under growing pressure to act after Europol linked hundreds of suspicious games worldwide to a criminal syndicate in the city-state.
Noble said the man was wanted in Italy because he is allegedly working for Tan Seet Eng, a Singaporean businessman, known as Dan Tan, for whom Italian authorities have issued an arrest warrant.
Italian police said Suljic wanted to turn himself in to Italian authorities and that he faces charges of criminal association and sports fraud.
In November, Serbian footballer Almir Gegic, who had also been wanted by Italian authorities, turned himself in at Malpensa.
Tan is accused of heading a crime syndicate that made millions of dollars betting on rigged Italian football matches.
Italian officials have been unable to take Tan into custody as the arrest warrant cannot be served while he is in Asia.
Acknowledging that Singapore has come under criticism for not detaining Tan, Noble said authorities there were restrained because they had to follow their own laws and could only take action when there was enough evidence.
However, Noble added that investigators worldwide have been slow to catch up with match-fixers because they were so far "not properly prepared to work together" and share enough information with their international counterparts.
Ralf Mutschke, FIFA head of security, said at the Malaysian conference that he hoped Tan would be brought to face the courts with the help of Singaporean authorities.
For their part, Singaporean police said on Thursday that Tan was "assisting" investigations.
Tan, who has been named in several investigations and is wanted in Italy, but denies wrongdoing, is "currently assisting Singapore authorities in their investigations", a police statement said.
It is the first time police have indicated Tan has undergone questioning.
Police also confirmed they gave the tip-off that led to the arrest of Sulic.
"The Singapore authorities have been offering assistance and sharing available information with affected countries and will continue to do so," the statement said.
The Singapore Police Force also announced on Thursday that four senior officers from the SPF and Corrupt Practices Investigation Bureau (CPIB) will be heading to the Interpol Headquarters in Lyon, France, to join the Global Anti-Match-fixing Taskforce.
Tan's former associate, Wilson Raj Perumal, has alleged to Italian investigators that Tan placed syndicate wagers on fixed games using Asia-based online betting sites via intermediaries in China.
A report by the EU's police agency earlier this month said organised crime gangs, including ones in Asia, have fixed or tried to fix hundreds of football matches around the world.
Europol said its 18-month review found 380 suspicious matches in Europe and another 300 questionable games outside the continent, mainly in Africa, Asia and South and Central America.