Police in Pakistan are stepping up a manhunt for a possible serial killer after an eight-year-old girl was found raped and murdered in Kasur, eastern Punjab, sparking widespread protests.

Government spokesperson Malik Ahmad Khan said authorities were searching for a suspect who kidnaps and kills young girls after Zainab Ansari’s body was found on Tuesday.

It comes after police revealed at least 10 similar cases had rocked the city since January 2017.

Investigators now say they have found traces of the same DNA on six of the girls, including Zainab, according to a police document seen by the BBC.

All of the girls, who lived within a 3km radius, went missing from near their homes and were dumped on rubbish sites or in abandoned houses nearby.

Speaking at a press conference on Friday, Mr Khan vowed to bring Zainab’s killer to justice and said chief minister Shehbaz Sharif would be personally following the case.

Police released an e-fit of the suspect after CCTV footage captured the unidentified man walking with Zainab on 4 January. Her body was found on a rubbish tip a mile from her home five days later.

Zainab’s father Ameen called on the government to publicly punish the perpetrator.

“If the culprits are punished publicly then it will serve as a deterrent for preventing similar cases,” he said, according to GeoNews.

Zainab’s family raised the alarm after she did not arrive home from her religious studies class earlier in the month.

Her 16-year-old sister Laiba spoke of the family’s anguish at what happened to her.

“I am not crying because she is dead. My heart breaks to think that she was hurt. I cannot bear it,” she told Dawn.

“How long will it take before you all forget about my sister?”