Revealing this and more, Fahim Ansari, now in the Mumbai police's custody, said the Lashkar-e-Tayiba had to shelve its plan after the crackdown following the attack on the Central Reserve Police Force camp in Rampur, Uttar Pradesh last January.
The Lashkar wanted to bomb the BSE because it would cripple India's financial capital.
Stressing that the planning was extensive, Ansari said his brief was to get acquire maximum information about several sites in India.
'My brief was to get maps and information about several places, but the specific brief was to get the maximum data on the BSE,' Ansari told his interrogators.
The bombs at the BSE were to be planted by Imran Shehzad, Ansari said, but he too was picked up by the police.
Explaining his journey into terrorism and the manner in which the Mumbai attacks were planned, Ansari said the main reason for him to take up jihad was because he hero worshipped Osama bin Laden. He disclosed he was awestruck by the manner in which the 9/11 attacks were carried out in the US.
Ansari said his first encounter with the Lashkar was in Dubai, where he then worked.
'After 9/11, I spoke to several people about my plans to join a terror outfit. The Lashkar was looking out for men to undertake India operations,' he told his interrogators.
Ansari then met a man named Abdul Azeez.
Azeez, sources told this correspondent, reported to Abu Cheema, and handled the recruitment of Indians who wanted to take up jihad.
After meeting Ansari in Dubai, Azeez returned to Pakistan and promised the Indian he would be taken to that country in a couple of days. Ansari told his interrogators he was taken to Pakistan through Iran.
Ansari said Lashkar terrorists Zaki-ur-Rehman Laqvi, Yusuf Muzzamil and Abu Cheema are in charge of India operations. Diabetes compelled Cheema to hand over charge to Abu Qama last year.
'The first person I met in Pakistan was Muzzamil who operated under the code name Abu Harara,' he said.
Abu Harara has been named by Faisal Sheikh, the man charge-sheeted in the July 11, 2006 attacks on trains in Mumbai.
'I was trained to become a complete fidayeen and my knowledge of Mumbai was utilised to the fullest,' Ansari told the Mumbai police.
He said the Lashkar made it compulsory for every would-be terrorist to undergo marine training. A majority of attacks, he was told, would be launched from the sea.
Pakistan naval personnel were actively involved in the marine training, he revealed. He was taught to use the geo-positioning system and the use of a compass so that navigation on the high seas was easier.
The marine training was imparted at the Lashkar headquarters in Murdike, Pakistan occupied Kashmir, and at the Mangla dam in Pakistan, Ansari added.
He was told that his role would not be limited to just being a fidayeen.
'I was supposed to help in gathering intelligence and also conduct a survey of specific targets. This was when Muzzamil told me about the Mumbai attacks. The course in gathering intelligence was known as Daura-e-Ribat. I had to specialise in it for a month. Muzzamil showed me the Google maps application. I was initially asked to survey the BSE, the airport, offices of Reliance and the Taj Mahal hotel. However, there was a change in plan. I did a survey of only those targets which were finally attacked,' Ansari told his interrogators.
Ansari returned from Pakistan on a fake passport.
'I first travelled to Nepal under the name Hammad and once I got clearance, I slipped into India. Abu Hamza (one of the main handlers for the Mumbai attacks) organised a driving licence for me in the name of Sahil Pavaskar which I used for identification purposes once I was in Mumbai,' he disclosed.
'In Mumbai, I spent most of my time photographing potential targets and collecting data. The main plan was to blow up the BSE. The Lashkar identified Imran Shehzad for the same. I enrolled myself as a student at a computer centre near the BSE so that I could collect information about the security around the BSE.'
The plan to bomb the BSE was shelved after Ansari and Shehzad were arrested after the Rampur attack.
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