Witnesses against four alleged members of a global football match-fixing syndicate are \"unwilling\" to testify for fear of reprisals, Singapore\'s interior minister said Monday. This has made it necessary for the four to be held under a special law that allows for indefinite detention, Minister for Home Affairs Teo Chee Hean said in a written answer to a question in parliament. A source had told AFP earlier this month that among those being detained under the Criminal Law (Temporary Provisions) Act is Singaporean businessman Dan Tan, the suspected syndicate leader. Teo said the special law is used \"as a last resort in cases where accomplices and witnesses dare not testify against criminals in court, for fear of reprisal\". He said the law is used against criminal syndicates and organised groups involved in serious crime such as secret society activities, drug trafficking and unlicensed money-lending. Teo said the the same considerations for using the special law \"were taken into account\" when he issued the detention orders against the four. \"Like drug-trafficking and unlicensed money-lending, illegal soccer match-fixing activities are carried out by organised criminal syndicates with complex and layered structures motivated by financial gain,\" he said. \"Witnesses able to provide testimony against the syndicate are unwilling to do so,\" he added. \"Additionally, where cross-border illegal activities are involved, the difficulties of securing evidence and witnesses willing to co-operate and testify against the syndicate in open court are amplified.\" Teo said the four suspects had been informed of the grounds of their detention. Dan Tan, also known as Tan Seet Eng, was among 14 suspected members of the match-fixing syndicate arrested by Singapore authorities during a crackdown in September. A source told AFP last month that the syndicate had rigged more than 100 football games worldwide in a scam worth millions of dollars, before it was busted. Interpol chief Ronald Noble said after the arrests in Singapore that the gang was the world\'s \"largest and most aggressive match-fixing syndicate, with tentacles reaching every continent\". Source: AFP