There’s no jury if you plead guilty. He didn’t have to be convicted because he admitted to the crime as part of a plea bargain.

Prosecutors in US conspire to deprive defendants of their rights by creating a 'plea bargain' system where federal defendants almost always plead guilty in exchange for not being 'taxed' with often multiples of the bargained number of years in jail for daring to exercise their right to trial, where they will be crushed by an asymmetric system of the massiveness of the US government verse whatever meager amount they have to spend on an attorney and expert witnesses.