He looked quite upset and loked a bit irritated even with Dilshaad when she approached him.
His bad mood continued when Tanu came in and he didn't even smile at her even if politely.
And everyone knows the way how he gave it to Tanu to learn something from Zoya.
All this makes me think that he got some news about Tanu through that phone call. May be, he came to know she lied about factory burning or something.
PS: I am more and more convinced he is doubting Billi and doing his own research after today's episode.