The roughing up of the family forced them to go into hiding for fear of being killed, and the fresh incident as the country is yet to recover from the assassination of outspoken governor Salmaan Taseer for his support to Christian women Aasia Bibi in jail on blasphemy charges.
According to media reports, the incident was triggered over a trivial dispute between a Muslim woman and her Christian sister-in-law, both residents of an east Lahore neighbourhood.
The two got into an argument on Tuesday night.
Though the matter was apparently settled, the Muslim woman walked out onto the street on Wednesday morning after her husband had gone to work and started shouting that her sister-in-law had abused Prophet Mohammed, The Express Tribune newspaper reported.
A short while later, a group of men led by Muhammad Sameer, a member of a religious organisation "keen on raising its sectarian profile," forced their way into the Christian woman`s house and started slapping her, said her brother.
"Other men and women from the neighbourhood started gathering at the house too and they beat up my sister and mother. They were the only people in the house," the brother said.
"We tried our best to get her to confess her crime," Sameer said. As a member of a religious organisation, he said he could not tolerate any derogatory remarks about the Prophet.
Khadim Hazoor, Sameer`s son-in-law, said faces of Christian women were blackened and they were made to wear necklaces of shoes and paraded around the neighbourhood on donkeys. The crowd showed no-mercy even as the women repeatedly touched the feet of the men denying committing blasphemy and asked for forgiveness.
Sameer said he was "very proud" of his wife for beating the Christian woman.
"She beat (the woman) more than anyone else. Her hand is so swollen that she hasn`t been able to make rotis since the day of the incident. I`ve been getting my meals from a restaurant," he said. The Christian woman`s family left the neighbourhood soon after the incident.
"None of our relatives is ready to let us stay with them. They fear the wrath of the extremists, particularly after the assassination of Salmaan Taseer," a male member of the family said.
He was referring to the recent killing of Taseer, the Punjab Governor, by a police guard who said he was angered by the politician`s criticism of the country`s controversial blasphemy law.
Mumtaz Qadri, the assassin of Taseer, is a member of the same group as Sameer, the man who led the mob that beat the Christian women.
The group also runs a 24-hour cable channel.
Hazoor said the people of the neighbourhood would not allow the Christian family to return to their house.
He claimed that the fight between the Muslim woman and her Christian sister-in-law revolved around the upbringing of Muslim woman`s 18-month-old daughter.
The Muslim woman wanted to raise her daughter as a Muslim but her sister-in-law wanted her niece to be raised as a Christian, he said.
Zameer Khan, an NGO worker, helped the family flee the neighbourhood after they were attacked.
"Apparently there was no blasphemy, just an argument between two women," he said. He said he had helped relocate the family temporarily.
Pakistan`s blasphemy law has been at the centre of a heated debate since a lower court in Punjab sentenced Asia Bibi, a 45-year-old Christian woman, to death last year for allegedly insulting the Prophet Mohammed.