Images generated using a face-recognition software, combined with careful study of CCTV visuals from Pune’s German Bakery where a bomb exploded on February 13 and comparison with photographs of suspects, helped police zero in on Abdul Samad Mohammed Zarrar alias Abdul Samad Bhatkal. The younger brother of Yasin Bhatkal alias Ahmed Mohammed Zarrar is the susptected planter of the bomb.

Abdul Samad was arrested by the Maharashtra ATS on Monday morning when he arrived from Dubai at Mangalore airport after a three-month visit to the UAE that had begun 10 days after the Pune blast.

He was remanded in police custody until June 1 by a Metropolitan Magistrate’s court for his alleged involvement in a little known case of 2009. He was booked under various sections of the Arms Act and the ATS made no mention of the bomb blast in the remand application.

But the Press Information Bureau issued a statement quoting Union Home Minister P Chidambaram as complimenting the ATS, Pune Police and Central agencies for apprehending Abdul Samad, “prime suspect behind the German Bakery blast”.

Inside the courtroom in Mazgaon, ATS officials furnished documents relating to a 2009 arms case in which Abdul Samad was a “wanted accused”.

Three alleged Chhota Shakeel men — Haji Imran, Suleiman Mehmood alias Katela and Afzal Shaikh alias Lala — who were arrested on August 5, 2009 had alleged that Abdul Samad was the man who supplied them three Chinese-made revolvers in Bangalore. The weapons were seized from the trio outside Sadanand Hotel in Mazgaon.

ATS officials, however, confirmed that Abdul Samad would be questioned on the Bhatkal links to the Pune blast. A Pune ATS team probing the blast has left for Mumbai.

“We suspect that Samad planted the bomb at the German Bakery. He was identified through CCTV footage obtained from a camera installed inside the bakery,” an officer said. A police informer from Bhatkal, sources claimed, had also identified the man in the CCTV footage.

Family members have denied this allegation, claiming they had evidence of Abdul Samad attending a wedding around the same time.

“We are producing witnesses who have seen Abdul Samad at his cousin’s wedding celebrations the whole week,” said Mohammed Ali, his paternal uncle.

Grainy images of the side profile of a suspect picked up from the closed circuit camera over the cashier’s counter at the bakery were enhanced using software that generates frontal images from side profiles, the sources said.

“Footage from the CCTV in Pune provided only the side profiles of a suspect believed to have planted the bomb. An effort was made by investigators to find software that can provide full face images from just side profiles. This helps narrow down the search to a great extent,” a senior official said.

The images generated using the face recognition software helped zero-in on Abdul Samad. In the initial phase of the probe, investigators had zeroed-in on the older Zarrar brother, known to be a key member of the Indian Mujahideen outfit that carried out a series of blasts across the country between 2007 and 2008, as the prime suspect.

In 2008, Abdul Samad had been investigated by police for a possible support role in terrorist acts of the Indian Mujahideen while he was a student in Bangalore but was let-off since there was no evidence of involvement. His brother remains untraced.

On his return to Bhatkal, Abdul Samad was called for a counselling session by police. He told police that his brother Ahmed was in touch with the family for a year after he went underground — he had called them from Dubai where he apparently worked as a salesperson in a shop in Al Ras.

A police officer said Abdul Samad came with his family and sat through the session “passively”, “occasionally nodding” to the advice that was being offered.

Senior officials who sat through the meeting gave “a good lecture” for over 30 minutes on how he should stay away from “the lines of Indian Mujahideen” and not follow the steps of Ahmed and his accomplices Riyaz and Iqbal. “He never argued. Only paid attention and left the station soon after the talk was over,” an officer recalled.