The Christian community in Pakistan has been the worst hit by extremist attacks over the past year - more Christians have died in these incidents than from any other community.
The targeting of the hospital and school, and now the Karachi charity, are the latest in a series of attacks against specifically Christian missions or places of worship.
Christian leaders such as Shahbaz Bhatti, head of the All-Pakistan Minorities Alliance, believe they are the innocent victims of fundamentalist rage over the US-led war on Afghanistan.
"The school attack [in Murree] is clear evidence of this," he said.
Human rights activists Cecil Chaudhry says Islamic extremists are applying "twisted logic" - they think that as Americans are largely Christian, therefore any Christians are the enemy.
Coping with prejudice
There is no clear figure for the number of Christians in Pakistan.
Cecil Chaudhry says that although the results of Pakistan's 1998 census have not been collated so far, he believes the community numbers about five million.
However, human rights activist Joseph Frances reckons there are almost double that number.
And according to the country's church records, there are closer to 10 million.
Discrimination has increased over the years.
Marginalisation
Cecil Chaudhry has first-hand experience of it.
A senior and decorated air force officer, he resigned when he was denied promotion and passed over by a lower-ranking Muslim officer.
And until the 1970s, his name had appeared in national school text books as a hero in wars with India. But at some point, it was simply removed.
"This marginalisation began in the era of former president Zia ul Haq and by 1983 or 1984 we had just been removed form the history books."
The year 1972 is seen by Christians as a turning point, when former premier Zulfiqar Ali Bhutto embarked on a nationalisation programme which seized Christian educational institutions.
Then there were a series of laws, including creating separate electorates for non-Muslims, drawing up new blasphemy laws and evidence laws which in effect made the testimony of a non-Muslim worth only half that of a Muslim.
Shahbaz Bhatti believes that anti-Muslim prejudice was encouraged to such an extent during the Zia era that deep-seated anti-Christian feeling has permeated Pakistani society.
Christians say religious intolerance is getting worse - not better - and that this is damaging the country's reputation internationally.
And the community believes it remains highly vulnerable to any backlash from the US-led campaign against the Taleban and al-Qaeda.