Complex sentence: Conventional interrogation is ineffective because the treating physician theorizes that DeSalvo suffers from a split personality; he has two identities that are unaware of each other, his "normal" personality fabricating memories in place of the memories of murder committed by the "strangler" personality.
Split into simpler sentences: Conventional interrogation is ineffective because the treating physician theorizes that DeSalvo suffers from a split personality; he has two identities that are unaware of each other. His "normal" personality fabricates memories in place of the memories of murder committed by the "strangler" personality.