A special court on Monday took cognisance of a supplementary chargesheet filed by the Central Bureau of Investigation in the AgustaWestland VVIP chopper scam case and issued summons to a former defence secretary and four retired Indian Air Force officials in connection to the matter, ANI reported.

Special Judge Arvind Kumar directed all the accused persons to appear before the court on April 28 for the next hearing.

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 CBI, 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.

On March 16, the CBI had filed a supplementary chargesheet against former Defence Secretary Shashi Kant Sharma.

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 CBI’s special team had taken over the case in 2016 and filed the first chargesheet against former Air Chief Marshal SP Tyagi and 11 others on September 1, 2017.

The agency alleged that Tyagi had 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 CBI has also alleged that three middlemen – Christian Michel, Guido Haschke and Carlos Gerosa – paid bribes to Tyagi and his relatives.