The Supreme Court of Pakistan on Sunday gave a 72-hour deadline to the Punjab police chief to arrest the culprit behind the brutal rape and murder of a seven-year-old girl that has sparked national outrage.

Police in Pakistan’s Punjab province has failed to nab the killer of Zainab, whose body was found in a garbage heap on January 9, despite carrying out DNA test of 800 suspects in over two weeks.

Chief Justice of Pakistan Mian Saqib Nisar held the hearing of the case at the Lahore registry and admonished the police officers for their failure to arrest the killer of the victim.

The parents of the eight girls who have been raped and murdered in Kasur since 2015 appeared before the Supreme Court bench and pleaded for justice.

“An unspeakable crime has been committed against an innocent girl,” Nisar said and ordered the Inspector General of Police to arrest the culprit in the case within 72 hours.

Zainab had gone missing while going for tuition near her house in Kasur city, some 50 kilometres from Lahore, on January 5.

Her parents had been in Saudi Arabia to perform Umrah and she had been living with her maternal aunt.

After her abduction, the footage showed her walking with a stranger near Peerowala Road. Police failed to trace her abductor and on January 9 her body was recovered from a heap of garbage near the Shahbaz Khan Road.

Autopsy report had confirmed that the girl was subjected to rape, torture and was then strangled to death.

The horrific incident triggered public outrage throughout the country with people demanding justice for the child.

The girl’s murder was the 12th such incident reported in Kasur district in a year.

A police officer told the Chief Justice that the DNA tests of 800 suspects had been conducted.

“The police are pursuing a one-track investigation and must widen the scope of the probe beyond simply using DNA testing to track down the culprits. The DNA tests of 21 million people will have to be conducted if the investigations continue in this way,” Nisar said.

No headway has been made in the case since the girl’s body was found, despite the Counter-Terrorism Department, Intelligence Bureau, Special Branch and Punjab Forensic Science Agency being tasked with investigating the case.

According to the initial investigation, the perpetrator of is a serial killer who may have been involved in some six or seven such incidents in Kasur.

Kasur had made headlines in 2015 when it was revealed that a gang of paedophiles was busted for running a child sex ring in the city.

Last year 4,139 incidents of child abuse took place in the province.