Risotto figures out that Doppio must be a Stand user that the boss trusts in deeply because he’s able to hear the noise from a certain Stand. Risotto then uses his Stand Metallic against him. Metallic is able to control magnetic force and attacks Doppio. Doppio uses the part of the boss’s power he received from him. While they’re fighting, Risotto realizes that Doppio’s personality and actions seem to be changing and he realizes exactly who Doppio is.
I had just thought that you were the 
boss's most trusted subordinate.
لقد كنتُ قد ظننتُ بأنّك أكثر تابع يثِق به الزعيم
Ich hielt dich für den Untergebenen,
dem der Boss am meisten vertraut.
Creía que eras el subordinado
en el que el jefe más confiaba.
Creía que eras el subordinado
en el que el jefe más confiaba.
Je te voyais comme l’homme
de confiance du parrain
Pensavo stupidamente che tu fossi soltanto
il sottoposto più fidato del boss.
Eu achei que você era apenas
o subordinado mais confiável do chefe.
Раньше мне казалось, что ты — самый близкий
к боссу человек, которому он доверяет.