Two double murders were reported on Tuesday at Netaji Nagar in the southern part of Kolkata and Narendrapur located in its southern fringes.
Bodies of an elderly couple - Dilip Mukherjee and Sapna Mukherjee - were found lying in a pool of blood on the first floor of their two-storied building at Netaji Nagar, Kolkata Police Joint CP (Crime) Murlidhar Sharma said.
Sapna's body was found near the door at the entrance of the first floor with a rope tied around her neck and a pipe inserted through her throat. Her husband's body was on a bed in a room.
"The incident probably had happened last night. Going by the initial probe it seems that one or two persons had entered the house. The house was totally ransacked. Our forensic team is examining the place," Mr Sharma said.
It seems that the two were gagged to death. The exact reason would only be known after the postmortem report, he added.
Police questioned the tenants of the shops in the ground floor of the couple's house.
A woman, who used to work as a maid for the childless couple, alleged that some people, probably promoters, were making threatening calls to them to sell off the house.
"Both of them were very well-behaved and had nobody to look after them," she said.
In the second incident at Narendrapur, bodies of Pradip Biswas and his wife Alpana, were found inside two suitcases in the washroom of a house where they worked as caretakers, police said.
As the owner of the house, who stays elsewhere, failed to contact the middle-aged couple over phone, he called up Pradip's brother Joy to look for them.
Joy found the bodies and informed the police.
Stench was emanating from the blood-stained suitcases, police said.
The bodies were sent for postmortem examination.