Security agencies are probing the use of ammonium nitrate used in the bomb that rocked Varanasi on Tuesday evening, killing one infant and injuring 32 others, including foreigners.
Preliminary reports suggest that the bomb that was assembled was very much like the ones that the Indian Mujahideen [ Images ] has used in its previous attacks.
Meanwhile, investigating agencies are probing the authenticity of the e-mail that has been sent out by the IM to different media houses following the bomb blast.
Although it has been traced to Malad, a suburb in Mumbai [ Images ], intelligence agencies say that there is still some work left before they can conclude regarding its authenticity.
The e-mail was dated on December 6 (Monday), but it was received only on December 7 (Tuesday) following the blast and agencies are trying to see if the attack was originally planned to coincide with the anniversary of the Babri Masjid [ Images ] demolition in 1992.
It is said that the operation may have been planned for December 6, but postponed due to heightened security at Varanasi ahead of a general alert that was issued by the Union home ministry.