Why I believe it's anurag is because since the party anurag was trying to provoke and instigate bajaj. He kept repeating do you want to kill me in the hopes that bajaj will say back what he said in front of a crowd of people. Then he told anupham how he believed bajaj was the one to frame veena and injure himself. Notice how anurag is copying everything bajaj is doing. This is where he gets his idea. Also that scene in the beginning with anurag trying to bribe the employee makes me believe he actually did and it's a setup. Right now the aunt is worrying over her image being tarnished with what she did with veena. She is trying to stay in bajaj good books. What does framing bajaj get her? She wants his money and power and taanvi is not married to bajaj yet.