The city, which had not witnessed any major act of terrorism since October 18, 2007 when twin blasts ripped through the home-coming procession of former prime minister Benazir Bhutto, after a relative calm for two years was rocked by five bomb blasts within a span of six weeks. In three of the recent bomb blasts, 80 people were killed and hundreds of others wounded, while the two other explosions reported at Paposhnagar and Qasba Morr had low intensity and therefore caused less damage. All the five recent blasts targeted mainly participants of Muharram and Safar processions.

However, investigation teams of the Sindh police seem to have divergent assessments about the involvement of different terrorist groups behind the twin blasts carried out on the day of Chehlum.

Linking the new ideas employed to carry out the blasts like the use of a TV casing and concealing an improvised explosive device in a cement block by the suspects arrested for the Ashura blast, the Special Investigation Unit chief suspected the involvement of Jundullah behind the twin blasts.

However, a police officer of another unit investigating the blasts was not impressed by the suspected involvement of Jundullah, for he is of the view that it's the clever work of suspects belonging to the Takferi school of thought.

Similarly, another investigator held a very divergent view and suspected the involvement of the Balochistan Liberation Army behind the twin attacks.

However, none of the investigators Dawn spoke to suspected the involvement of the Taliban.

“We have still not seen a signature of the Tehreek-i-Taliban Pakistan (TTP) in the five terrorist strikes that have taken place in the city in a short span,” said a senior investigator.

Surely they (TTP) didn't have any shortage of suicide bombers, and employing them in the city was no difficult task for them, the officer observed.

Interestingly, the intelligence agencies in a report passed on to the police before the Chehlum procession had warned that “a suicide bomber in disguise of a woman wearing black burka, hand gloves and socks could make his way into the procession to blow himself up”.

On the contrary, however, terrorists targeted mourners outside the main procession in a highly sophisticated manner twice on Feb 5.

Arguing over the possibility of Jundullah's involvement, a senior officer observed that instead of carrying out more attacks in the city, the terrorists belonging to the outfit should be on the run after four members of the group were taken into custody for their involvement in the Ashura blast.

The officer rejected the impression that Jundullah was essentially an outfit comprising youths from certain localities, saying that it now had a multiethnic composition.

Some investigators said Laskhar-i-Jhangvi did not have the potential or expertise in carrying out such orchestrated attacks.