Complex sentence: Parke's suspicions are confirmed when the ADI found inside Jo Powers's brain turns out to contain a manifesto written by Garrett: he wanted to force people to face the consequences of their actions and not be able to hide behind online anonymity.
Split into simpler sentences: Parke's suspicions are confirmed when the ADI found inside Jo Powers's brain turns out to contain a manifesto written by Garrett. The manifesto further states that he wanted to force people to face the consequences of their actions and not be able to hide behind online anonymity.