According to CBI's case before the court, Indrani Mukerjea killed Sheena Bora because she was furious over the relationship between Sheena Bora, whom she introduced as her sister to everyone, and Rahul Mukerjea, son of Peter Mukerjea from his first marriage.

How Sheena Bora was murdered?

Sheena Bora was murdered in April 2012 allegedly by Indrani Mukerjea, Rai and Indrani's ex-husband Sanjeev Khanna. The case was first detected by Mumbai police in 2015, when Rai was arrested with an illegal pistol. In the course of questioning, he blew up the lip covering the killing of Sheena Bora.

How did Indrani Mukerjea kill her daughter?

It was Rai's allegation that Indrani had planned it and had discussed it with her ex-husband, Sanjeev Khanna. He alleged that Indrani had surveyed a likely area to dump the body the evening before the murder. ... He said they took her to one of the by-lanes in Bandra and Khanna strangled her.