Crimes Aaj Kal S03 E04 The Vanishing

21 year old Suyash Kolhe, a 2nd year engineering student, in Pune, goes missing. Suyash stays with his sister, Mansi (19) years old, also a student. They both stay on rent in a small flat. The strongest suspicion is on Mansi, who is having an affair with a guy Anand and Suyash was opposed to it. But if it's a forced disappearance, then where are the signs of it?