A 12-year-old Christian domestic servant in Pakistan is believed to have died as a result of mistreatment at the hands of her Muslim employers.

The family of Shazia Masih say she was mentally and physically abused in the Lahore home of Muslim lawyer Chaudhry Mohammad Naeem, where she had worked for the last eight months to support her poor parents.

Shazia was taken to hospital for treatment but did not recover and passed away on January 22. A post mortem at Mayo Hospital in Lahore confirmed the cause of death as torture.

The family is being aided by CLAAS, a ministry that supports persecuted Christians in Pakistan. Director Joseph Francis accompanied them to the police station to register a first information report with the police against Naeem, whom they accuse of killing Shazia. Police were initially unwilling to register a case against Naeem but backed down after CLAAS put pressure on them by contacting human rights advocates and helping to raise awareness of Shazia's death in the media.

Mr Francis and other human rights advocates joined a protest by local Christians outside the Punjab Assembly Hall in Lahore the following day. They received assurances from the police that they would do everything they could to see that justice was done for Shazia and her family.

Mr Naeem initially fled before being arrested by police two days after Shazia’s death. He told police he punished Shazia for repeatedly misbehaving and helping herself to food. His wife and sister-in-law were also arrested, while his son was granted pre-arrest bail by the high court in Lahore. Muslims responded to the arrest of Naeem and his family by protesting outside the police station. They claim the detentions are illegal and are demanding their immediate release.

Shazia’s death has been taken seriously by local and federal politicians. Her family have received visits from Ministers for Minority Affairs Shahbaz Bhatti and Kamran Michael, and the chief minister of Punjab Mian Mohammad Shabaz Sharif, who promised that Naeem would be arrested and punished.

Thousands turned out for Shazia's funeral at the Catholic Cathedral in Lahore on Monday. Church leaders present included the Archbishop of Lahore the Most Rev Subastine, Bishop of Lahore the Rt Rev Dr Alexander John Malik, and the Bishop of Iran and Gulf the Rt Rev Azad Marshall. Also present were Minister for Minority Affairs Shahbaz Bhatti and Minister for Minority and Human Rights in the Punjab Kamran Michael.

In addition to arranging for the post mortem and organising the funeral, CLAAS has provided Shazia's family with free legal advice, financial support and basic necessities.

CLAAS says the murder of Shazia not only exposes the brutal persecution of Christians by Muslims, but also the exploitation of children forced to work for next to nothing and often in poor conditions. Shazia was working for just 1,000 rupees (£13) a month to support her poor parents. Her job as a maid with Naeem required her to live at his home full-time. Her mother Nasreen says she was not allowed to visit her daughter and that Naeem did not pay her for Shazia's work.

Despite repeated efforts to make contact with their daughter, the first news they heard of her came last Friday when Naeem visited to tell them that Shazia had been admitted to hospital that morning in a critical condition. It was upon arriving at the hospital that Nasreen discovered her daughter had in fact died as a result of her injuries.

Nasir Saeed, head of CLAAS in the UK, said the existence of 10 million child labourers in Pakistan was an “obvious violation” of the child labour laws, which prohibit the employment of children below the age of 14.

“The murder of Shazia is not an isolated act of violence. Domestic servants are often subject to brutal violence and the government at the provincial and federal level is failing to put a stop to it,” he said.

“The government must enforce the child labour laws across Pakistan and prosecute those who continue to employ children and abuse them.”

He added: “The exploitation of children is directly related to the widespread poverty and unemployment blighting Pakistan, and the failure of the government to provide free education to children. Unless the government takes concrete steps to bring in universal education, there will be many more Shazias.”