What makes this complicated is Sudha's schizophrenic attribute - had Devika been an original individual, rather than a derivative personality of Sudha, who could have given the police an original and accurate statement, things would have been fine. However, the fact that Sudha has no recollection of what Devika faced and did makes it look like Devika had something to hide, which she didn't, and that's what makes this worse.
Hopefully, tonight, when Kalpana interrogates her and she discloses what really happened, the police will let her off.