The Central Bureau of Investigation (CBI) has stared its probe in the alleged suspicious transactions of Rs 22 crore involving non-existent entities in India and Singapore in Malaysian carrier AirAsia.

The case is already being probed by the Enforcement Directorate.

Top CBI sources said that the agency is scrutinising the evidences in the allegations before filing the preliminary enquiry or an First Information Report.

In 2013, Tata Sons had joined hands with Malaysian carrier AirAsia and Arun Bhatia's Telestra Tradeplace to start low cost carrier AirAsia India.

The carrier had to wait for nine months before taking off.

In September 2013, Tata Group had joined hands with Singapore Airlines to start a new full-service airline in India, 18 years after a failed attempt.

Tata Sons owned 51 per cent stake in the carrier, which has been christened as Vistara, with Singapore Airlines holding the rest.

In October 2015, Tata Groups ex-Chairman Cyrus Mistry had claimed that a forensic investigation had revealed fraudulent transactions of Rs 22 crore involving non-existent entities in India and Singapore.

As a bitter war plays out between Mistry and Tata Groups interim Chairman Ratan Tata, the former had alleged that due to the latters passion for aviation, the Tata Sons Board increased capital infusion into the aviation sector at multiple levels of the initial commitment.

In a letter written to the Board members of Tata Sons, Mistry, a day after he was ousted on October 24, said that "board members and trustees are also aware that in the case of AirAsia, ethical concerns have been raised with respect to certain transactions as well as overall prevailing culture within the organisation".

"A recent forensic investigation revealed fraudulent transactions of Rs 22 crore involving non-existent parties in India and Singapore," it said.