There are many reasons why I think this is the case
1. Firstly only the Major could have seen the reports that Rajveer sent, saying that Dr. Ritu is the spy, and also have copies of the same
2. Secondly, in yesterday's episode, the major walked into Rajveer's room well after Ritu had left and then he asked R whether Ritu was in love with him. He could have said that only if he had seen a display of affection from Ritu's side, which means he would have known about the hug and the bug! Raj never told him about it
3. I thought the silhouette of the person talking to Ritu and his voice looked like the Major's
My theory is this.
He is a senior person in the army and wants the triggers without damaging his reputation. By assigning Raj this role and Ritu as the spy, he is the mastermind and in a position when even though he is very close to the triggers, noone will suspect him if anything goes wrong. Last time Navin got framed and this time if anything happens, Rajveer would get into trouble.
Please comment on how plausible this theory sounds
Regards