The official refused to divulge the date when Nalini, a senior Chennai-based lawyer, will be questioned, but said the agency has "certain evidence" against her in the case, and for this she has been asked to appear before the investigators in Kolkata.
Nalini has been given 10 days' time to appear before the investigators.
Sources said the agency wants to get information about the "transaction details" from Saradha company to Nalini's accounts and its "purpose".
Earlier, the ED and the Central Bureau of Investigation (CBI) both have questioned Nalini in the case but ED this time wants to quiz her on the basis of some "new evidence".
Nalini came under the ED's probe ambit after Saradha Chairman Sudipta Sen alleged he had paid over Rs 1 crore to her at the instance of Manoranjana Sinh, the estranged wife of Congress leader Matang Sinh.
Nalini was the lawyer for drafting a contract for Saradha case accused Maoranjana, who was arrested by the CBI in October 2015 along with Santanu Ghosh, a businessman, in connection with the chit fund scam.
Sen made the allegation against Nalini through his letter to the CBI in April 2013. He also told the agency that he had paid for Nalini's visits to Kolkata and for her stays at a five-star hotel.
He also alleged that Nalini pressured him to invest Rs 42 crore in Manoranjana's company.
