Despite their apparent success at dismantling several terror modules last year, there is one hitch which remains a 'cause for concern' for the elite special cell of the Delhi Police.
On the evening of January 13 last year, a special cell-led operation aimed at nabbing two Pakistan-trained bombers, known by their aliases Waqas and Tabrez, had not worked out at Mumbai's Byculla area, apparently because of 'a slight miscommunication' with their Maharashtra counterparts.
"We were on the brink of catching them when our cover was blown last year," said an officer. "Investigation revealed that they've been found to have been actively involved in three terror plots: while two of these were successful, one, fortunately, wasn't."
A year later, the duo, who belongs to home-grown terror outfit Indian Mujahideen (IM) and are suspected of having planted bombs during the Mumbai serial blasts of July 2011, an unsuccessful bid at Pune in August 2012 and given the task of executing the same in Delhi, during the festive season of 2012, remain on the run.
According to sources, they had entered the country using forged travel documents from the Indo-Nepal border in late April 2011, before travelling to Madhubani and then to Mumbai.
The explosives used by them to execute the 7/11 blasts, sources said, had apparently been procured from Udupi in Karnataka.
In January 2012, a special team of the Delhi Police had reached Mumbai after interrogation of eleven alleged IM operatives, led them to Naqi Ahmed, a leather businessman based in Delhi's Shaheen Bagh.
Naqi introduced the duo to Rubina Begum, who later became their landlord at Habib building.