Mumbai, Dec 8 (PTI) A father-son duo were picked up for questioning here in connection with the e-mail sent by banned terror group Indian Mujahideen to several media houses claiming responsibility for the Varanasi blast.

The terror mail traced to a residential complex in Navi Mumabi had claimed responsibility for yesterday's blast at a crowded bathing ghat in Varanasi that left a child dead and 37 others injured.

The five-page email sent by Indian Mujahideen has been sent using an unsecured WiFi of Airtel Broadband of the two, official sources said.

The two were questioned and later released, they said.

Mumbai Police Commissioner Sanjeev Dayal told PTI that the email has been traced to Navi Mumbai and the police of that area and Mumbai Police were coordinating to trace the culprits.

Terrorists of Indian Mujahideen have been using unsecured WiFi connections for sending mails to media houses within minutes of blasts taking place.