The silent ways in which law enforcement works are often misunderstood by some in the media, says a match-fixing investigator.
The SI Sports Intelligence investigator, who wants to be known only as John because of his undercover work, was responding to Mr Declan Hill's allegations about match-fixing suspect Dan Tan Seet Eng being "protected".
The former police officer, who joined the hunt for global match-fixers two years ago, said: "Some investigations are complex and require years of thorough investigation to meet legislative requirements to lay charges."
Investigators need resources and cooperation from other agencies to prove the elements of each offence, he added.
"It's no point taking out one guy from a syndicate and calling that a success," he said.
"It's better to conduct thorough investigations which provide accurate information leading to substantial arrests and success in disabling a syndicate's capabilities and functions."
Mr Davy Chan, 66, a retired cop and Police Gallantry Medal winner, also reacted strongly against Mr Hill, saying: "No such thing. What's he talking about? Singapore is no different from other police forces worldwide.
"Before you can arrest somebody, you must have concrete evidence. Otherwise, your weak evidence will backfire in court."
Tan is wanted in Italy for allegedly masterminding more than 30 fixed matches in Italy's Serie A and Serie B.
He is said to have made millions of dollars, aided by members of a Balkan syndicate.
In Hungary, Tan has been charged in absentia for a similar role.
Mr P. Sivakumar, the former deputy general secretary of Football Association of Singapore, said: "I don't know what evidence Mr Hill has to imply that the Singapore authorities are protecting Tan.