Bharatiya Janata Party (BJP) leader Subramanian Swamy on Monday wrote to the Acting Director of the Central Bureau of Investigation (CBI) to probe into the role of former defence secretary Vijay Singh and Tata Sons interim chairman Ratan Tata in the Agusta Westland chopper scam.

Talking to ANI about his letter, Swamy stated that he has urged the CBI acting Director to look into the matter of how Ratan Tata appointed Vijay Singh to the board of Tata Trusts, which in itself is illegal.

"Ratan Tata went and deposed in Italy in the trial in the Agusta scam, so that itself makes it necessary to interrogate Mr Tata, because how is he involved? If he can obey a summons from Italy, he can obey one from India also," Swamy said.

Further stating that all allegations made by sacked Tata chairman Cyrus Mistry so far have been proven true, the senior BJP leader added, "For instance the Air Asia scandal has been proved by records and Delhi High Court has taken notice of it. So, here also it is necessary for the CBI to summon both Vijay Singh who was defence Secretary and also Ratan Tata and interrogate them."

Accusing Ratan Tata of conspiring with Singh, Swamy states in his letter that the ex defence secretary had engaged in corrupt practices in the Agusta Westland scam, which the CBI is currently probing.

"Ratan Tata thereafter rewarded Vijay Singh with a directorship in Tata Sons by the dubious route of being a nominee in the Tata Trusts which in itself are illegal since the Tata Trusts are Trusts for philanthropy and owned by the public and not by the Tatas," the letter said.

Asserting that a complaint has been filed in this regard with Securities and Exchange Bank of India (SEBI), Swamy added that such Trusts cannot engage in commercial business even if under the name of Tata and Sons Ltd.