Sources said that the Detection of Crime Branch (DCB) of Ahmedabad Police have established that a mobile phone believed to have been used for the planning of the Ahmedabad blasts was also being used in Delhi until about a month before the serial blasts there.

While the DCB has so far arrested 21 alleged SIMI activists in connection with the Ahmedabad blasts, several others remain at large — among them are Abdus Subhan Qureshi alias Tauqeer, Qayamuddin Kapadia, Abdul Razaq Mansuri alias Mohammed Ismail, Mujib Shaikh and Alamzeb Afridi.

Police investigations and the interrogation of those arrested suggest that local SIM cards were purchased under fake names and used only until July 26, presumably to avoid being tracked. “These people had bought SIM cards providing fake identities around the first week of July. These SIM cards were bought from different places in Ahmedabad using forged documents. They were supposed to get rid of the SIM cards and the cheap mobile sets on the night of July 26 itself,” an investigating officer told The Indian Express.

While tracking these phone numbers, DCB officers discovered that most sets had stopped functioning after the Ahmedabad blasts but one number was being used in Delhi. “While most numbers were non-functional since the night of July 26, three were used from different locations in the state until July 30. One of the numbers, however, was being used in the Hazrat Nizamuddin area in Delhi until August 5. We suspect that the mobile phone was being used by someone on our most wanted list,” the officer said.

Sources said an Ahmedabad police team was even sent to Delhi to try and investigate “the lead”. When contacted for details, Ashish Bhatia, Joint Commissioner of Police, DCB, declined comment: “These are operational secrets.”