The National Investigation Agency (NIA) has said Malgonda Patil, the prime accused in Margao blast, stayed in the saint's quarter 'Sant Kakshay' at Sanatan Sanstha's Ramnathi Ashram in Goa.
Patil, 28, stayed next to the room of the Sanstha founder Jayant Balaji Athwale, it said.
"Malgonda Patil was an active member of Sanatan Sanstha involved in the publicity of Sanstha and used to hold satsang (meetings) at various places. He stayed in Abhyasika/Sant Kakshay of Sanatan Sanstha Ashram building in Ponda," the NIA said in its chargesheet.
Right-wing Hindu organisation, Sanatan Sanstha, had initially distanced itself from all the accused in the Margao blast.
NIA filed the chargesheet on May 17 in south Goa district court, a copy of which is with the PTI.
Malgonda Patil, who died while ferrying the explosives in Margao, was the Managing Trustee of Dharma Prachar Sabha, a trust of Sanatan Sanstha.
The investigating agency also found that Malgonda Patil and another accused Dhananjay Ashtekar hatched the blast conspiracy at the former's room, which was close to the room of Jayant Balaji Athawle on the Ashram's first floor during June 2009, four months before the blast.
Investigators have found that Margao blast was just a loop in the serial blast planned at five different places across Goa on October 16, 2009. (More) PTI RPS YRM
The accused were seekers (sadhakas) of Sanatan Sanstha and opposed Narakasur (mythological demon) competition, which is held in Goa on Diwali eve. They termed the practice of glorifying Narkasur as it is 'against Hindu religion.'
NIA took over the probe from Goa police's special investigation team on December 24, 2009. The investigators have chargesheeted eleven people, including two who died in the bomb explosion, four arrested and five who are absconding.
"Custodial interrogation of the absconding accused is needed to unearth the larger conspiracy of this case," the 3,000-page chargesheet reads. It has sketched how the entire conspiracy took shape and the required devices to assemble Improvised Explosives Device (IED) were procured from different places including Ichalkaranji and Mumbai.
A Google search was used to download the circuit required to assemble IEDs. While first test blast was conducted in August 2009 on a hillock at Talaulim village in Goa, the probe has revealed that second test blast was conducted at Jath, Sangli in Maharashtra during last week of September 2009. Malgonda Patil was a native of Jath.
On the D-day the accused divided into two groups armed with the explosives. While Malgonda Patil and Yogesh Naik, both accused, were assigned the job to plant a bomb at Margao, another group, Vinayak Patil and Vinay Talekar had planted the bomb at Sancoale, 20 kms away from Margao.
NIA has managed to recover unexploded devices, which were thrown from a bridge at Borim village by the accused when they realised that Margao plant went haywire and police had diffused two IEDs at Sancoale.