Haroon Naik, arrested in connection with the 13/7 serial blasts here, had undergone training with Indian Mujahideen founder Yasin Bhatkal in Pakistan and sent Rs 10 lakh to him last March to carry out the bombings that killed over 25 people.
Naik was on Wednesday produced before a magistrate and was remanded in the custody of Maharashtra Anti-Terrorism Squad until February 10 for his alleged involvement in the conspiracy of carrying out the blasts.
According to the remand note submitted by ATS to the court seeking the accused's custody, Naik had gone to Pakistan in 2005 via Nepal and met Bhatkal there.
"The duo underwent training in explosives and weapons there. In March 2011, Naik sent Rs 10 lakh through Hawala from Saudi Arabia to co-accused Kanwar Nain Wazeer Chand Patrija (also arrested in the case) to be handed over to Bhatkal," the note alleged.
According to the investigating agency, the amount was used by Bhatkal to carry out the blasts on July 13, 2011 at three locations - Zaveri Bazaar and Opera House in south Mumbai and at Dadar in central Mumbai.
The agency sought Naik's custody to find out if he had sent money to IM operatives before March 2011.
"It also needs to be ascertained under whose instructions Naik is operating and had sent the money. We need to interrogate him (Naik) to find out who is his financer," the ATS said.
Naik has been shown as an arrested accused in the Opera House blast.
