I wonder if Abhi secretly asked the doctor to do a DNA test too when Tannu had her pregnancy test (secretly because he feared PraNu won't allow if asked directly), the results of which came later and she told him the father is not him..
Or he overheard Tannu talking to someone after his "sorry" to her... Tannu runs away saying she will be back...Abhi goes in search of Pragya but misses her as she leaves in a taxi. May be then, Abhi saw Tannu talking to someone and eavesdropped.
I can't find clues yet to see if Pragya has plans against Tannu... Burning the pics could have been a clue.. but I wasn't convinced. Pragya if she knows Tannu is lying doesn't need to play games with Abhi and Daadis anymore.
Or Meetu met or meets Abhi/Pragya and gives a clue about Tannu's other BF!
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