Intermittent rains in the city on August 1 when four explosions occurred on the bustling Jangli Maharaj Road, adversely affected visibility of the CCTV footage seized from the establishments near the blast sites.

As most of the CCTV cameras at the actual blast sites ---- Balgandharva Theatre, McDonald outlet and Dena Bank branch--- were found to be non-functional, the investigators probing into the seemingly abortive serial blasts here have been trying to analyse the footage available with other commercial establishments in the vicinity to look for suspicious movements of possible suspects.

Confirming poor quality of the CCTV footage available, a senior police officer said, "The visibility of CCTV footage recovered from some of the establishments on JM road is not clear as it was raining on the evening of blasts."

City police commissioner Gulabrao Pol, who confirmed visibility problem with the CCTV footage, said the work of analyzing the CCTV clips was voluminous and time consuming.

Police have seized CCTV footage running into several hours from shops, hotels and commercial establishments on the arterial road which witnessed the bomb explosions.One person was injured in one of the blasts that occurred near Balgandharva Theatre.

The investigators, comprising Maharashtra ATS and city crime branch, who carried out a sustained interrogation of Dayanand Patil, the lone injured person in whose bag the explosive went off, have so far drawn a blank with no concrete clue emerging, sources said. 

The poor visibility of CCTV footage which reportedly presents blind spots in the screening is also coupled with breaks in power supply in the city on the evening of the blasts, sources said.

Although it is believed that ammonium nitrate was the chemical used by the culprits to engineer the explosions with detonators and digitised timers, police are still not officially confirming the forensic lab report establishing the nature of explosive which apparently failed to achieve the desired magnitude as it went off.

One of the reasons being cited for low intensity of the blasts is that the chemical powder was damp due to the wet weather.

Records of Cell phone calls that were made at the time of the incident was also being examined for more leads in the case that has not yielded any breakthrough even after a week, sources added.

Meanwhile, Maharashtra Deputy Chief Minister Ajit Pawar has announced that a provision of Rs 30 crore will be made to procure about 1000 CCTVs in and around Pune as the city has been on the terrorists' radar since the German bakery bombing in February 2010, which was seen as a second major attack after the 26/11 Mumbai carnage.