PNB Fraud: Gokulnath Shetty is alleged to have played a key role in the Rs 13,700-crore loan fraud (File)

Gokulnath Shetty, a former banker and key conspirator in the multi-crore PNB scam in which diamond merchants Nirav Modi and Mehul Choksi are prime accused, on Wednesday declined to give his consent for undergoing polygraph and narco-analysis tests.

Earlier this month, the CBI had moved a plea before a special court here, seeking it's permission to conduct polygraph and narco-analysis tests on Shetty, a former deputy manager at PNB's Brady House branch in Mumbai.

While seeking nod for the scientific tests, the central agency had said it needs to know about the "pecuniary benefits" received by the accused.

In his application submitted before special CBI judge VC Barde, Shetty declined to give his consent to undergo the tests and rejected the charge of receiving pecuniary gains from the scam.

Shetty is alleged to have played a key role in the Rs 13,700-crore loan fraud while working at PNB's Brady House branch in south Mumbai.

He was arrested in March last year, weeks after the mega scam came to light.

Shetty, in his plea, said the CBI's allegations about pecuniary gains or such advantages were just "assumptions" and further investigation on this aspect was not required.

The former PNB executive also cited health grounds for objecting to the central investigating agency's plea.

Shetty, in his application, said he is in jail for the last 18 months during which, he claimed, his physical and mental health has deteriorated.

Claiming he has always cooperated with the probe, he prayed to the court to reject the CBI's plea.

Polygraph or a lie-detector test is conducted using a device or procedure that measures and records several physiological indicators such as blood pressure, pulse, respiration, and skin conductivity while a person is asked and answers a series of questions.

In the narco-analysis test, a person is put in a semi-conscious condition in which imagination is neutralised, thus making it difficult to lie.

Various government agencies, including the CBI, are currently probing the mega fraud and making efforts to bring back Nirav Modi and Mehul Choksi from abroad to face trial.

The matter will come up for further hearing on August 28.

The scam related to issuance of fraudulent Letters of Undertaking (LoUs) by PNB to companies of Mehul Choksi and Nirav Modi since March 2011 in alleged connivance with bank officials.

An LoU is a guarantee given by an issuing bank to Indian banks having branches abroad to grant short-term credit to the applicant.

In case of default, the bank issuing the LoU has to pay the liability to the credit-giving bank along with the accruing interest.