Pune: Union Home Minister Sushil Kumar Shinde on Saturday is expected to visit the sites of Wednesday's bomb blasts.
Shinde, who took over as Home Minister on the same day after P Chidambaram was made Finance Minister, will review the security situation at a meeting with top officials here.
Four low-intensity bomb blasts in quick succession shook Pune on Wednesday night, leaving one person wounded, while a fifth device was defused.
The blasts on Wednesday had come on the same day as a scheduled visit -- cancelled at the last minute -- by Shinde.
While the first three explosions took place within a one kilometre of the busy Junglee Maharaj Road, the fourth blast was reported from the Garware Chowk.
A fifth bomb was defused near a McDonalds outlet in the city.
While initially it was suspected to be an act of mischief, a splinter group of the Indian Mujahiddeen (IM) has now emerged as the prime suspect, but investigators are also probing other angles.
The police has also prepared sketches of two suspects however they haven't been released to the public just yet, media reports said.
The investigating agencies have also reportedly approached mobile operators to help trace any suspicious calls made before or after the blasts in Pune on Aug 1.
Meanwhile, the person injured in the blast, 34-year-old tailor Dayanand Patil who was initially considered a suspect after being wounded by the explosives that he was carrying, has been let go.
Earlier media reports said that design flaws in the bombs that went off in Pune on Wednesday prevented wider carnage, as investigators began to sniff a larger terror plot contradicting initial suspicions that the explosions were someone's mischief.
The bombs, the caused four explosions in quick succession on Wednesday evening in Pune while one was defused, were meant to cause greater damage but a design snag led them to go off partially, thereby preventing the shrapnel from spreading.
The conclusion was reached after investigators conducted detailed analysis of the two unexploded improvised explosive devices (IEDs) and the nature of blasts that had left one person injured.
Forensic analysis also revealed that ammonium nitrate was most likely used in the bombs and that wrist watches were used to trigger the explosives.
Maharashtra Home Minister R R Patil said on Thursday: "According to preliminary reports, ammonium nitrate was the primary ingredient used in the devices which were apparently triggered by electronic triggers."
Referring to a purported threat letter received by Pune police after the killing of an Indian Mujahiddeen (IM) operative Qateel Siddiqui in Yerawada Central Jail on June 7, Patil said the security agencies were checking the letter for terror links.
Official sources have already been quoted as saying that the manner in which in which locally made watches were used as a timer to complete the bomb circuit to trigger battery-operated detonators, were reminiscent of the style of IM.
In February 2010, a bomb explosion outside the popular German Bakery near Pune's famous Osho ashram left 17 people dead as arrested Lashkar-e-Taiba (LeT) operative David Coleman Headley, a Pakistani American, confessed his role in the terror strike.