Sources said the ED has summoned officials concerned in the Games body to appear before it with the required documents and clarify certain details to it.
ED has filed a case under the Prevention of Money Laundering Act (PMLA) to investigate the money trail in the scam.
Besides this, the Central Bureau of Investigation and Central Vigilance Commission are also looking into alleged irregularities in the overlays scam. The CVC has put overlays contract worth Rs 668.49 crore under its scanner.
"We have asked for certain documents and details of money transactions, bidding and eligibility criteria of the contractors. The documents are under examination and certain questions in this regard will be put forth to Kalmadi," ED sources said.
The Directorate will soon seek the court`s permission to question Kalmadi, who was recently arrested by CBI on charges of cheating, conspiracy and corruption in the Commonwealth Games scam. He has now been sent on judicial custody till May 18.
Sources said that the Directorate will also be questioning some of the OC officials for their alleged involvement in the scam.
OC Secretary General Lalit Bhanot and Director General V K Verma have already been arrested by CBI in this case.
Kalmadi has been arrested by CBI for alleged bungling in the Rs 141 crore Time Scoring and Result (TSR) contract given to a swiss firm.
The CBI has so far registered eight cases of which three are related to restoration work of two sporting venues, two are related to Queen Baton`s relay, while one each is related to overlays, contract given to Swiss Time Keeping, and contract given to SIS live for the coverage of the Games.
CBI has also arrested Sandeep Wadhwa, MD of Comfort Net which is a part of the Switzerland-based Nussli India consortium, in overlays scam.