LAHORE: The arrest of 23-year-old rape-murder suspect Imran Ali on Tuesday has brought authorities a step closer to getting justice for Zainab Ameen, but the profile of the ‘serial killer’ had been developed months earlier.

“We had already developed the profile of the perpetrator based on the seven other [rape] cases in a Kasur locality,” says Punjab Forensic Science Agency Director General Dr Muhammad Ashraf Tahir.

“Results of samples collected in case of previous victims matched the results of the DNA of the perpetrator in Zainab’s case.”

“The police were looking for a serial killer,” Dr Tahir says, adding that even before Zainab’s case gained national attention, 71 suspects were brought in for a DNA test. But the suspect remained at large.

“The police tried what was humanly possible for the earlier cases, but this case was pursued on a war footing,” he says.

He describes the PFSA’s work for Zainab’s case — 24-hour shifts; 20-hour windows for processing of tests and batches of 100 samples — as “unprecedented”.

Dr Tahir explains how they zeroed in on the suspect through the “process of elimination”.

“We worked with the police to create a radius of 2km and got the data of all the residents in that area. Through the CCTV footage, we estimated the age of the perpetrator to be between 20 and 45 years old, so we began to eliminate all women, children and the elderly living in that locality.”

He says the forensic teams went from door to door to collect samples of 1,150 people. Imran Ali was the 814th person whose sample was collected for testing.

“This man gave the sample, but he pretended like he had a heart attack. The team didn’t pay attention at the time because they had the swab, but suspicions were raised.”

“When we found the match, I didn’t tell anyone. Because I wanted to reconfirm and reanalyse the DNA to make sure he is the only one,” the PFSA head says.

He then asked the police to bring this suspect, along with five others, to the lab in Lahore for re-testing.

“I didn’t even tell the IG police. I said I wanted to redo sampling of six people. So they were brought from their homes. Imran was one of them,” he says.

When asked to comment on the PFSA’s assertion that police crime units are weak at collection evidence, Crime Record Office SP Muhammad Yousaf said his team members were trained by the agency and adept at collection.

“We try our best for evidence not to be wasted. We try to get to crime scenes as fast as possible but if the general public or media contaminate a crime scene, it is not our fault,” he said.

Published in Dawn, January 25th, 2018