Pakistani Minister for Minorities Shahbaz Bhatti, who had called for changes in the country's controversial blasphemy law, was killed in a gun attack in Islamabad on Wednesday, officials said.
The anti-blasphemy law has been in the spotlight since November when a court sentenced a Christian mother of four to death, in a case that has exposed deep rifts in the troubled Muslim nation of more than 170 million people.
While liberal Pakistanis and rights groups believe the law to be dangerously discriminatory against the country's tiny minority groups, Asia Bibi's case has become a lightning rod for the country's religious right.
In January, the governor of the most populous state of Punjab, Salman Taseer, who had strongly opposed the law and sought presidential pardon for the 45-year-old Christian farmhand, was gunned down by one of his bodyguards angry about the governor's stand.
Here some facts about the blasphemy law.
* The law has its roots in 19th century colonial legislation to protect places of worship, but it was during the
military dictatorship of General Mohammad Zia ul-Haq in the 1980s that it acquired teeth as part of a drive to Islamise the state.
* Under the law, anyone who speaks ill of Islam and the Prophet Mohammad commits a crime and faces the death penalty but activists say the vague terminology has led to its misuse. The law stipulates that "derogatory remarks, etc., in respect of the Holy Prophet either spoken or written, or by visible representation, or by any imputation, innuendo or insinuation, directly or indirectly shall be punished with death, or imprisonment for life, and shall also be liable to fine."
* Christians who make up 4 percent of Pakistan's population have been especially concerned about the law saying it offers them no protection. Convictions hinge on witness testimony and often these are linked to personal vendettas, they say.
* Blasphemy convictions are common in Pakistan, although the death sentence has never been carried out. Most convictions are thrown out on appeal, but angry mobs have killed many people accused of blasphemy.
* In 2009, 40 houses and a church were set ablaze by a mob of 1,000 Muslims in the town of Gojra, Punjab. At least seven Christians were burnt to death. The attacks were triggered by reports of the desecration of the Koran. Police had already registered a case under Section 295C against three Christians for blasphemy.
Last July, two Christian brothers accused of writing a blasphemous letter against the Prophet Mohammad were gunned down outside a court in the eastern city of Faisalabad.
Hence a conviction or even an accusation under this law is often a death sentence, activists say.
* Some attempts have been made in the past to either repeal the law or try and amend the provisions to prevent their misuse, but each time the government has faced the wrath of religious conservatives. The current administration has ruled out scrapping the law altogether, saying such a move would hand a weapon to religious extremists and fuel militancy at a time when it is struggling to tackle it.
* Islamist parties have warned against any attempt to change the law, seeing it as a dilution of the country's Islamist character under foreign pressure. Thousands of party supporters have staged street protests, saying any attempt to change the law would only be "over their dead bodies."
* In December, a pro-Taliban Muslim cleric offered a $5,800 (3,573.41 pounds) reward to anyone who killed the Christian woman, Bibi, in prison, angered by attempts, by among others governor Taseer, to save her from the gallows.
(Writing by Sanjeev Miglani; Editing by Robert Birsel)