Body of a newborn was recovered from Nadia's Chapra area on Thursday morning.
Some local residents witnessed the body wrapped with a plastic bag by a pond. They called up the police.
"We rescued the body of the baby boy and sent it to a hospital. He was declared brought death there. We took the body for post-mortem," said a police officer.
"We believe the baby died in the hospital. But we have to investigate who brought the body outside the hospital. It may be any hospital staff or parents of the baby boy," said the investigators.
Meanwhile, the police discussed the incident with hospital authority.
The Bengal police and investigators of Criminal Investigation Department (CID) unearthed several child trafficking rackets across the Bengal recently.
Many people including some doctors and health officials of private hospitals and nursing home were arrested.
It should be recalled that the local resident rescued body of a newborn baby from a canal at Dum Dum on a few months back.
The local residents spotted the body at the canal side. Later, police rescued the body from there and took it to hospital.
The hospital authorities declared the baby brought lifeless. The baby was around a month old.
In the most recent event, ten babies were rescued from a charitable home for the mentally disabled and the elderly at Behala.
Skeletons of two children were also found at the premises of the office of the same charitable trust that runs the home.
This was only the second such raid after police recovered three newborn babies from a nursing home near Kolkata, which were supposed to be sold.
In the above-mentioned case in Nadia on Thursday, police interrogated seven persons.
"Most of the persons were the staff of the hospital," said a police officer.
The officer further added: "We suspect that there may be many child trafficking racket operating in the hospital. The baby was taken out for sale, but somehow
the baby died. The accused kept the baby by the bank of the pond."