The investigative agency informed that now they are looking for the owner of a cellphone which was used only twice for receiving calls from Mumbai before the blast at Sheetla Ghat on Dec 7, 2010.
According to Indian Express, the mobile phone had a pre-paid connection, issued in Mau town, near Varanasi, just six days ahead of the blast.
However, the identity and address proof submitted with the application for the mobile connection, was found as fake.
The bomb blast on Dec 7, outside a temple during the Ganga Aarti ceremony in Varanasi killed 1 baby and injured other 32 people including an Italian national.
Read: Mumbai police arrests 2 linked to Varanasi blast
Uttar Pradesh police arrested two people so far in connection with the bomb blast.