When a small Malaysian academic publisher printed a book on the death penalty in Singapore by a little-known British freelance journalist, neither could seriously have expected it to make much of a splash in the tightly-controlled city-state or beyond.

That all changed when, in the early hours of July 18, the Singapore police arrested the author, Alan Shadrake, in his hotel room, shortly before he was to meet reporters about the content of his book.

Shadrake was subsequently charged with contempt of court, with government prosecutors alleging that his book, Once a Jolly Hangman: Singapore Justice in the Dock, impugns the impartiality, integrity and independence of the judiciary. A criminal defamation complaint filed by the Media Development Authority, Singapore's censorship body, is still under investigation.

Singapore's government insists that its draconian laws, including the mandatory death penalty for the trafficking of even small amounts of illegal drugs, help keep crime and social disorder down, ensuring that the city-state remains a popular center for international business and tourism.

Although the arrest of the 75-year-old writer once again thrust Singapore's strict limits on freedom of speech into the international limelight, the global media interest has quickly, and predictably, faded.

It remains to be seen whether Shadrake's book, which argues that Singapore's use of the death penalty is uneven and unjust, will have any lasting impact in a city-state where there is little public debate on sensitive issues such as capital punishment because of a combination of government secrecy, repression and self-censorship.

Having re-examined a wide range of drug trafficking cases over the last two decades, Shadrake claims that the likelihood of offenders being sent to the gallows is dependent on their socio-economic background and, in the case of foreigners, Singapore's economic and political relationship with their government.

Compare the fates of Julia Bohl, a German student believed to be part of a high-society drug-dealing ring in Singapore, and Amara Tochi, a young Nigerian hoping to carve out a career in football who unwittingly became a drug mule. Bohl was arrested in 2002 in possession of 687 grams of cannabis, well over the 500 gram limit above which a sentence of death by hanging is mandatory. Her predicament generated a lot of press coverage in Germany, an important trading partner for Singapore, and her government came under pressure to try to save her from the gallows. Fortunately for Bohl, before her trial began, further laboratory testing revealed that the drugs in her possession only weighed 281 grams. She was eventually sentenced to five years in jail and released after three years because of good behavior.

Tochi was not so lucky. He was arrested at Changi Airport in possession of more than 700 grams of heroin but insisted that he thought he was carrying African herbs. Tochi did not attempt to flee when told by airport staff that the police were coming to talk to him and the trial judge accepted that there was no evidence that he knew he was carrying drugs. But he was executed nevertheless in 2007.

Shadrake argues that the judiciary and the police offer a sympathetic ear to members of the domestic elite or overseas citizens from key economic and political allies while showing a disturbing eagerness to expedite the execution of suspected drug mules from poor or marginalized backgrounds, sometimes in highly questionable circumstances.

The author quotes an anonymous former officer from Singapore's Central Narcotics Bureau, who says that zealous undercover police often encourage traffickers to transport larger amounts of drugs so that they cross the mandatory execution threshold.

Undercover officers also played a key role in the demise of Vignes Mourthi, a young Indian Malaysian hanged in 2003 for trafficking 27.65 grams of heroin despite his insistence that he believed he was carrying incense stones. One key piece of evidence against him was an unsigned, undated statement from an undercover officer who claimed that Mourthi had admitted to him that he was carrying drugs.

Yet just two days after Mourthi's arrest, the same undercover officer was arrested on suspicion of rape and was subsequently convicted of corruption for attempting to bribe the alleged rape victim to withdraw her complaint against him. Although such behavior ought to have cast serious doubt on the quality of his testimony, the officer was not tried until a year after Mourthi's execution and no mention was ever made at Mourthi's trial of the severe question marks surrounding the officer's conduct.

Shadrake argues that Mourthi's execution is "arguably one of the most appalling miscarriages of justice in Singapore's history" and the publication of his book has provided new impetus to the Mourthi family's campaign to clear his name posthumously.

In what is a polemical and sometimes repetitive book, Shadrake makes no secret of the fact that he is opposed to the death penalty on principle. But, using a mixture of publicly available legal material and interviews with sources from different parts of Singapore's justice system, including extensive interviews with the former chief executioner, he seemingly does enough to convince even proponents of the death penalty that it is time to reassess the way Singapore handles capital cases.

Furthermore, Shadrake argues that "the egregious record of Singapore in relation to the death penalty cannot be separated from its deeply-embedded structures of authoritarianism and political illiberalism".

In countries where genuine free speech is allowed, local journalists often lead the way in holding the judiciary and the police to account. But Singapore's leaders have always insisted that the city-state's reporters eschew "Western-style" confrontational, investigative journalism in favor of a pliant, nation-building "Asian" approach.

Little wonder then that they are pursuing Shadrake through the courts, the ruling People's Action Party's preferred means of silencing dissenting voices.

When his trial opened on July 30, those journalists present, both local and foreign, were warned by the prosecutor that they too could be charged with contempt if they republished any of Shadrake's "contemptuous" claims.

Yet despite the government's insistence that Shadrake's book "scandalizes the judiciary", the Media Development Authority says it has not banned the book, although it admits sending a letter to some bookshops warning them about the legal implications of selling it. The book no longer appears to be on sale in Singapore but it is available in the reference section of Singapore's National Library.

The government's response has generated much-needed publicity for the book, which the publishers said has sold 4,000 copies so far, making it one of the better selling socio-political works about Singapore.

But while the government's latest act of repression may appear at first sight to have backfired, all the attention generated by Shadrake's arrest sends a clear message to Singaporeans: delve into sensitive issues such as the death penalty at your peril.

Ben Bland is a freelance journalist who was formerly based in Singapore. He blogs at http://uk.asiancorrespondent.com/the-asia-file.