According to ED sources, during questioning Vikash Sihna had admitted to using an alloy making firm to route Koda's illicit money through hawala network.
Sources said he has also admitted about taking about Rs 40 crore in cash to Kolkata for illicit investments on behest of his brother, who was another close associate of the former chief minister.
Sinha, who was also questioned on the foreign trips taken by him along with other accused in the case, has also revealed trails of money and investments made abroad.
Vikash, in his Income Tax returns, had mentioned Rs 2,94,526 as income during 2005-07 which increased to Rs 24 lakh during 2007-08.
ED sources said Koda, who has been booked under Prevention of Money Laundering Act (PMLA), would now be questioned not only on the basis of documents seized but also on the statements of Sinha.