The Gujarati couple found dead at their residence in Bhowanipore was killed by someone close to them, a senior police officer said on Tuesday.
The deaths might have links to the share market in which the couple had significant investments, he said.
Police are also trying to find whether the couple had taken any loan from anyone to invest in the stock market, he also said.
"Circumstantial evidence indicates that those who came to their house were known to them and the woman might have opened the door. There is a deep injury on the shoulder of the woman whose body was found lying near the entrance," he added.
Businessman Ashok Shah and his wife Rashmita Shah were found dead in their apartment on Harish Mukherjee Road on Monday evening.
Police have recovered the shell of a bullet from one of the rooms.
The mobile phones of the couple have been recovered and their call logs are being checked.
