The CBI has filed a supplementary charge sheet in the Rs 3,700-crore AgustaWestland scam against former Defence Secretary Shashi Kant Sharma and four Indian Air Force personnel, officials said Wednesday.

The CBI filed the charge sheet after getting the nod from the government to prosecute Sharma, who was the Defence Secretary between 2011 and 2013 before being appointed the Comptroller and Auditor General.

The central probe agency has also named the then Air Vice Marshal Jasbir Singh Panesar (now retired), deputy chief test pilot S A Kunte, the then Wing Commander Thomas Mathew and Group Captain N Santosh, they said.

Kunte and Santosh retired as air commodores. The alleged scam relates to the purchase of 12 VVIP helicopters from AgustaWestland.