The Central Bureau of Investigation has filed a supplementary chargesheet in the AgustaWestland chopper scam against former Defence Secretary Shashi Kant Sharma and four retired Indian Air Force personnel, The Indian Express reported on Wednesday.

The four former Indian Air Force personnel who have been named in the chargesheet include Air Vice Marshal Jasbir Singh Panesar, Deputy Chief Test Pilot SA Kunte, Wing Commander Thomas Mathew and Group Captain N Santosh.

The Rs 3,600-crore alleged scam is related to the 2010 purchase of 12 VVIP helicopters from Italy-based chopper manufacturer AgustaWestland, a subsidiary of defence manufacturing company Finmeccanica. According to the Central Bureau of Investigation, several parameters such as the height of the cabin of the helicopter and the maximum altitude that it could reach were tweaked to benefit AgustaWestland.

The central agency has filed the supplementary chargesheet in a Delhi court after receiving the Union government’s sanction to prosecute Sharma, PTI reported.

The Central Bureau of Investigation’s special team took over the case in 2016 and filed the first chargesheet against former Air Chief Marshal SP Tyagi and 11 others on September 1, 2017, NDTV reported.

The agency alleged that Tyagi recommended a relaxation in some parameters to benefit the helicopter manufacturer. He allegedly did so at the behest of top officials of AgustaWestland and Finmeccanica.

The Central Bureau of Investigation has also alleged that three middlemen – Christian Michel, Guido Haschke and Carlos Gerosa – paid bribes to Tyagi and his relatives.

The agency has alleged the helicopter deal incurred an estimated loss of 398.21 million euros (about Rs 2,666 crore) to the Indian government. The Enforcement Directorate, in its chargesheet, has alleged that Michel had received 30 million euros (about Rs 225 crore) from AgustaWestland.

On Friday, the Delhi High Court dismissed Michel’s bail plea.