"One thing that is clear, Sunday's attackers were not Iraqi. Survivors said they heard non-Iraqi Arabic dialects, and there were Yemeni and Egyptian passports at the scene. WaPo says the attack was in response to some charges of kidnapping Muslim women in Egypt.
The president called [Arabic] for more security at Iraq's churches. And the prime minister, who continues to emulate Baathist tacts, had the Army brigade commander of the area arrested presumably because the massacre took place on the commander's watch. The government also shut down the TV station Baghdadiya, charging it with terror connections.
Who knows why Iraqis threaten al-Qaeda. Maybe it's because it was for the longest time a country of many, many minorities who knew how to co-exist. Maybe they hadn't given it any thought. They just knew such violence is possible in an Iraq with compromised security."
A commenter (Mister Ghost) wrote that even if the killers were not Iraqi, they must have received support from Iraqis. Good point. This has been the case since 2003. I wouldn't be surprised if Saddam-lovers or Iraqi Sunni fundamentalists have supported Al-Qaeda since 2003. But then Mister Ghost says "al-Qaeda operates well within the precepts of Islam - the Christians are infidels."
The problem with Mister Ghost's argument is that Al Qaeda has killed many more Iraqi Shia Muslims than Christians. Yes Al Qaeda uses those verses from the Qur'an (kill the "unbelievers") to justify their murder of Christians, but Al Qaeda has used these same verses to justify their murder of Iraqi Shia. Al Qaeda has also murdered many Iraqi Sunnis. "Unbeliever" is whatever Al Qaeda wants it to be.