ISLAMABAD: Even as the banned Tehreek-iTaliban Pakistan`s (TTP) Jamaatul Ahrar faction claimed responsibility for the Friday attack on the Imambargah Abu Rizvia, investigators are looking into the possibility that the explosion may be linked to a man who faces the death penalty for killing the imambargah`s former caretaker.

Aun Mohammad Rizvi, a former controller at Pakist an Television, was murdered in October 1999. The man accused of killing him, Hafiz Mohammad Nawaz, was found guilty and awarded the death penalty. The sentence was challenged, but upheld by the Supreme CourtonOct5,2011.

The imambargah that was attacked on Friday is run by Rizvi`s family.

Syed Ibn Muhammad Rizvi told Dawn that Hafiz Nawaz was due for execution soon. Police had contacted Aun Mohammad`s family to find out if they had been approached for a settlement by the convict`s family.

However, he rejected the possibility of forgiving the condemned man.

Hafiz Nawaz is said to be the nephew of Riaz Basra, one of the most influential leaders of the banned Lashkar-i-Jhangvi (LJ).

Regional Police Officer (RPO) Akhtar Umar Hayat Laleka told Dawn that police were exploring links between the Imambargah bombing and the execution of Hafiz Nawaz.

`Police will interrogate the convict if necessary. However, a few suspects connected with the bombing are in police custody, the RPO said.

A joint investigation team consisting of police and intelligence officials, has been formed to investigate the bombing.

Planted bomb? Bomb disposal experts have disputed eyewitness claims that the bombing was a suicide attackand said in their report there was no doubt that a device containing two kilograms of high intensity explosives was planted near the entrance of the imambargah.

`Yes, it was a planted device, but we cannot be sure whether it was a timed or a remote-controlled device,` a member of the bomb disposal squad told Dawn.

He said the explosive was planted in a drain pipe serving a house opposite the entrance of the imambargah.

The explosion left a seven-foot hole in the wall of the house.

`There were some pieces of the metal which was used to make the bomb. These have strengthened our report,` he said, adding that had it been a suicide attack, the bomber`s body parts and splashes of blood would have been found all around.

`No nails, ball-bearings or pieces of a suicide jacket were found from the scene of this blast,` the expert said.

Responsibility: TTP Jamaatul Ahrar spokesman Ehsanullah Eshan called journalists on Saturday to claim responsibility for the attack on the imambargah. Ehsan, who was using an Afghan mobile number, said `we are undeterred by military courts and will continue our activities`