Singapore Court of Appeal has ordered the release of the alleged mastermind behind a global football match-fixing ring, ruling the detention as unlawful.

Dan Tan, also known as Tan Seet Eng, was among the 14 people arrested in Singapore’s biggest crackdown on match-fixing in September 2013.

Tan was accused of being a mastermind of a crime syndicate that has made its trade by fixing football matches around the world including Italy’s Serie A and Serie B. He was also charged by a Hungarian court in May 2013 for the same offense.

The alleged match-fixing kingpin was detained under Criminal Law (Temporary Provisions) Act, which allows the Minister of Home Affairs to detain suspects indefinitely without trial. The law is typically used against drug and illegal gambling bosses, loan sharks and members of underground syndicates.