A special CBI judge Arvind Kumar extended the custody of Shivani Saxena, an "active" director of Dubai-based Ms UHY Saxena and Ms Matrix Holdings, after she was produced before the court from her earlier ED custody.
The ED had arrested Saxena on July 17 from Chennai.
The agency had said in a statement that she was arrested under the provisions of the Prevention of Money Laundering Act (PMLA).
Ms Saxena and her husband Rajiv are residents of Palm Jumeirah in Dubai, an archipelago which is home to the most expensive properties in the United Arab Emirates (UAE).
The ED had alleged that the two Dubai-based firms Ms Saxena was involved with were those "through which the proceeds of crime had been routed and further layered and integrated in buying the immovable properties/shares among others" in this case.
The agency had said that in its probe it had found that AgustaWestland, United Kingdom "paid an amount of Euro 58 million as kickbacks" through two Tunisia-based firms.
"These companies further siphoned off the said money in the name of consultancy contracts to Ms Interstellar Technologies Limited, Mauritius and others which were further transferred to Ms UHY Saxena and Ms Matrix Holdings Ltd, Dubai and others," it had said.
The ED had also claimed that Ms Saxena's husband Rajiv is the "beneficial owner of Ms Interstellar Technologies Limited, Mauritius."
The ED, in this case, had also arrested Delhi-based businessman Gautam Khaitan last year and he is out on bail at present.
The probe in the deal had gathered pace after a Milan (Italy) court sometime back sentenced Italian defence and aerospace major Finmeccanica's former chief Giuseppe Orsi and AgustaWestland CEO Bruno Spagnolini on corruption charges in the sale of these helicopters to India.
The Milan court order also mentions the name of former IAF chief SP Tyagi at several points.
Post this, the ED and the CBI began a fresh round of questioning of the accused in this case and collection of further evidences.
The ED had registered a PMLA case in 2014 and had named 21 people including Mr Tyagi in its money laundering FIR.
On January 1, 2014, India scrapped the contract with Finmeccanica's British subsidiary AgustaWestland for supplying 12 AW-101 VVIP choppers to the IAF over alleged breach of contractual obligations and charges of paying kickbacks to the tune of Rs 423 crore by it for securing the deal.