I think she got to know every thing in yesterday's epsde itself yaaar... While going to hotel in the auto Ashok might have called her and told her about Ishita's fake possesssion and her acting to know about the informer... So yesterday when Ishita asked her she took Mihir's name... That's it ... Aur hamari DETECTIVE Ishita ko ek second me BEWAKOOF bana diya...
From then she started spying on Ishita tooo... And in today's episode she listened to Ishgun's phone conversation and informed about it to Ashok... So he reached there... Seriously yaar... Ishita planned the entire ghost drama to prove herself as ghost and today even without any re-confirmation she came to a conclusion that Sarika is innocent...The brains of the YHM characters dont work when necessary ... When unnecessary they work like super computers...