The letter, posted on messaging app Telegram on Sunday, also demanded payment in crypto currency and provided a link to a webpage for depositing it.
IT company HCL's Shiv Nadar was the third wealthiest Indian with a fortune of USD 27 billion while some peers in the tech industry dominated the list of fastest growing wealth.
A senior police official said that all possible angles were being investigated in this connection.
According to the police, the Scorpio was stolen from Vikroli on February 17.
Police said that they have obtained CCTV footage from multiple locations where the car passed in Mumbai.
The FIR has been registered at the Gamdevi Police Station against unidentified persons, a Mumbai Police spokesperson said.
The vehicle was found on Carmichael Road near `Antilia', Ambani's residence, a police official said.
It said that the proposed reorganisation eases the formation of strategic partnerships and stake sales to potential investors focussed on investments in oil-to-chemicals businesses.
Vodafone Idea (Vi) saw no real change in fortunes, continuing to lose subscribers at a rapid clip (56.9 lakh) during this month too.
Future Retail contended that Amazon was not concerned if the deal falls through then all the shops of the Indian company would be closed down.
Biyani said Future Group had approached them several times after its retail business was massively hit after the lockdown and its debt level zoomed.
However, things turned out of control when power supply at around 1,800 Jio towers in Punjab were either cut off or disconnected by local people.
Fines of Rs 25 crore and Rs 15 crore have been imposed on Reliance Industries Ltd (RIL) and Ambani, respectively.
Future Group requested SEBI to expedite the review of the proposed deal and issue a no-objection certificate, while Amazon has urged that the review of the 'impugned transaction' be suspended.
IMG-R is engaged in the business of creation, management, implementation and commercialization of sporting, fashion and entertainment events in India.