'The Mumbai police should study the bank accounts and flow of money in and out of the accused's bank accounts.' Indrani Roy/Rediff.com reports from Kolkata.

The Sheena Bora murder case gets murkier with each passing day.

Sheena's younger brother Mikhail has been flown to Mumbai on Friday, August 28, for interrogation, the Mumbai police hope to make a breakthrough in the case soon.

A senior police officer at Kolkata's Hastings police station shared some of his observations on the case during an informal chat with Indrani Roy/Rediff.com

The police arrested Sanjeev Khanna, Indrani Mukherjea's former husband, from a friend's home on August 26.

Khanna, who is accused of being present in the car when Sheena was allegedly murdered in April 2012, was flown to Mumbai on Thursday, August 27, for interrogation.

"The police need to find answers to some intriguing questions," the police officer at the Hastings police station, who spoke on condition that he would not be identified by name for this report, said. "Each answer will reveal an interesting angle of the murder case."

Some questions in the police officer's opinion:

• Where is Siddhartha Das, the so-called biological father of Sheena and Mikhail Bora? A section of the media reported that Das is dead. How did he die? In natural or mysterious circumstances?
• According to reports in a section of the Assamese media, Sheena and Mikhail were born to Indrani out of wedlock. In that case, who is their biological father?
• What led to Sanjeev Khanna and Indrani Mukherjea's divorce? Indrani apparently shared some information with Khanna before she left him and moved to Mumbai in the late 1990s that reportedly left Khanna speechless. What was that information?
• Why would Sanjeev Khanna get involved in Sheena's murder especially when his marriage to Indrani ended acrimoniously? Was he under any financial stress?
• Was Sanjeev Khanna 'blackmailed' into being an accomplice to the crime?
• Did he agree to 'assist' Indrani so that he could see his daughter Vidhie more often? Vidie, Indrani and Sanjeev Khanna's child, had been legally adopted by Peter Mukerjea after he married Indrani.
• Khanna is said to have met his ex-wife Indrani frequently in Mumbai. Why?
• Is Indrani's husband Peter Mukerjea as ignorant of the whole matter as he claims to be?
• It has been alleged that the Mukherjea couple transferred large sums of money from INX Media and INX News, the companies they founded in 2007, to various family members, including Sheena. Did Sheena refuse to transfer the money back to her mother?

The Hastings police station officer felt the key to the murder mystery may lie in the money trail.

"The Mumbai police should study the bank accounts and flow of money in and out of the accused's bank accounts," he said. "The money trail, I think, is sure to lead to the whole pattern of the murder conspiracy."