KARACHI, May 14: Police on Friday claimed to have achieved a breakthrough in the investigation into the May 7 Hyderi Mosque bomb explosion which left 19 people dead and 91 injured.

According to well-placed sources, police have succeeded in identifying the suicide bomber and have picked up four suspects belonging to the banned Sipah-i-Sahaba Pakistan.

The sources said that the man who had blown himself up in the Hyderi Mosque was a worker of the banned militant group. He had taken part in the jihad in Afghanistan and later joined police as a constable. He was identified as Mohammad Akbar.

"We have almost identified this man as the suicide bomber and statements of witnesses also substantiated his presence in the mosque," an investigator told Dawn. The sources said that four of his close associates had been detained for interrogation. The police were also searching for his two associates who had passed out of the Saeedabad police training centre and were posted at different police stations.

Police were also examining the record of the Baghdadi police station which had issued a character certificate to Akbar.

The suspects, according to the sources, said they had joined the police force to get secret information for their group.

The sources said that the investigation advanced swiftly after a policeman's buckle was found in the wreckage on Thursday. The buckle was inscribed with number '8242'. Inquiries revealed that the buckle had been issued to one Akbar, who had joined police as a constable in the year 2002. He was sent for police training in September 2003 to Saeedabad Police Training Centre.

The sources said that Akbar, a resident of Daryabad, Niazi Chowk, in the Baghdadi area of Lyari, had been missing since May 5, from the training centre. His family was contacted and they said that Akbar had gone out on Wednesday (May 5) and had not returned.

The sources said that Akbar was a die-hard worker of the banned group. "Akbar had done his intermediate and it is being investigated that how he was appointed in the police department and whether any inquiry about his character had been undertaken."

"We have obtained samples of Akbar's belongings from his home and these samples along with specimen of the limbs of an unidentified person, were sent for DNA tests. We believe the limbs were of Akbar but things would be clear only after the DNA tests."

The investigators had found two pieces of a burnt police belt and a melted police badge in the wreckage of the Hyderi Mosque and they initially believed that the suicide bomber could have been in a police uniform.

They said that statements of two witnesses, a bank officer and an employee in an insurance company, substantiated the presence of a man in police uniform.

According to the witnesses, the man in police uniform was also carrying a briefcase.