Andrew and Nicola Forrest’s private investment chief was deeply involved in decisions made by Fortescue as the ASX-listed mining giant considered deals worth hundreds of millions of dollars, according to evidence provided to a court.

The Forrest family controls almost 37 per cent of Fortescue. Andy Vesey, an executive at the company, told a Connecticut court that John Hartman – at the time the chief investment officer of Tattarang and now its chief executive – was intimately involved in Fortescue’s push into clean energy.