He writes books about sex, religion and politics, is critical of Islamism...and lives in Saudi Arabia. Gulf News  reports that the novelist Turki Al Hamad had been detained last month, did not come as a surprise.
However, it was not a book, but a tweet that broke the camel’s back.
On 22 December, Al Hamad - whose novels are banned in Saudi Arabia, Bahrain, and Kuwait - wrote :
@TurkiAlHamad: Our Prophet has come to rectify the faith of Abraham, and now is a time when we need someone to rectify the faith of Mohammed.
In a country like Saudi Arabia, there is nothing more dangerous than religion. Faced with the world’s fastest growing population of Twitter users, the government is making clear that it will not tolerate theological debate online.
The arrest of Al Hamad contradicts the image of Saudi’s relatively liberal Twittersphere. The New York Times ’ October 2012 article, “Saudis Cross Social Boundaries on Twitter,” argued social media has brought new freedoms to Saudis:
Open criticism of the state has long been taboo in Saudi Arabia...But after the Arab uprisings in early 2011, Saudis began taking to Twitter in vast numbers to express their frustrations, offering a new window into an opaque and profoundly conservative country...critics of various kinds – from prominent lawyers to feminists to ordinary citizens – have acquired large followings as they deplore corruption and injustice. Most Saudis now seem to post under their own names and photographs, a bold step away from the timid anonymity of the past.
Saudi’s are certainly active online and it is true they do criticise corruption and oppression. But Twitter is also subject to a great deal of self-censorship. There remain “red lines,” and religion is a major one of these.
The Saudi royal family has long been extremely hostile to differing religious interpretations. They have long repressed Saudi Shi’as . Shocked Muslims worldwide watched last year as the Saudi government bulldozed  religious sites in Mecca, which did not fit their strict interpretation of religion. Now, this campaign is turning its attention online.
In April 2011, a royal decree was passed, cracking down on electronic communications that insult Islam. In December last year, Raif Bedawi, a 30-year old website editor from Jeddah, was condemned to death. His crime - setting up a website in which users could discuss the difference between “popular” and “politicised” Islam. This month, Saudi writer, Hamza Kashgari, was arrested for tweeting about the Prophet Mohammad.
Tweeters and bloggers may be allowed to complain about the government, but to debate Islam would be to debate the very basis of the state. The royal family relies on legitimacy conferred from the clerics. The state was founded on the fundamentalist Wahhabist school of Islam. It is this school that justifies the Saudi king as the rightful “guardian of the holy places.” Court rulings — used to control dissidents — are rooted in unmatched freedom to interpret religious laws.
With the detention of such a prominent figure as Al Hamad, the House of Saud is indicating that religion can’t be questioned, even if its only in 140 characters. As Eman al-Guwaifly  wrote, the message they are sending is:
If we have arrested Turki al-Hamad, who has not been writing anywhere except Twitter, then none of you is safe.