New York (AFP) – Disgraced crypto wunderkind Sam Bankman-Fried was the mastermind behind a scheme to defraud FTX clients of billions of dollars, the star witness in his US trial testified on Tuesday. Caroline Ellison, Bankman-Fried’s former business partner and girlfriend, said that they had stolen “around $14 billion” from clients of the cryptocurrency exchange platform before it collapsed into bankruptcy late last year. The 31-year-old Bankman-Fried, co-founder and former CEO of FTX, has been charged with seven counts of fraud, embezzlement and criminal conspiracy, and if convicted could fac…