The woman, who abducted the three-day-old baby from the Calcutta Medical College and Hospital, had acted as a pregnant woman for three months inspired by Vidya Balan's 'Kahaani', according to an initial probe by the police.
The arrested woman, Chinmayee Bej, residing with her daughter and husband in the same Bagmari area where the baby's family resided, claimed that it was her baby whom she had given birth to yesterday, a Kolkata Police officer said.
Later, she admitted that she had stolen the baby boy on the pretext of giving him vaccination.
The police officer said, "The woman admitted to the crime. During grilling she said she had a miscarriage earlier after which she struck upon the idea of acting as a pregnant woman because she was deperate to have a boy."
The police said it was not ruling out the angle of enmity between the two families either.
Besides investigating whether Chinmayee got the help of a relative working at the hospital, the police is also looking into if the husband-wife duo had any connection with a child trafficking racket.
Meanwhile, a local court today sent the couple to nine days' police custody.
Though the police were not ruling out possible enmity between the two families, there could be other reasons too for the crime.
City Police Commissioner Rajeev Kumar said it was being investigated whether there was any 'foul play' in the theft of the baby.
Asked who would get get the Rs one lakh award the police announced last night for information on the theft, Kumar said, "The reward will go to the people who helped in tracing the baby. But if any foul play is found then of course the reward will not be paid.
"The reward is for giving information. We have to understand that the accused did not stay very far away from the locality where the victim stays," Kumar said.
The woman with the baby was found from a spot which is only a few metres away from the complainant's residence in Bagmari area of north Kolkata.
On whether the entire matter was a scripted one, he said,"I cannot comment on that because the investigation is still ongoing."
According to an official, police were looking into the angle of "an understanding that went wrong" between the accused and the family of the baby.
There could be a monetary transaction too between the two families regarding exchange the baby, he said.
"The accused woman was desperate for a boy and she may have contacted this Naskar family. It's still not clear. We are questioning the accused, her husband as well as members of the baby's family," the official said.
The arrested woman has an eight-year-old daughter but was desperate to have a son after a miscarriage around three months ago.
It seemed that when she found that Saraswati gave birth to a boy she planned of stealing it, he said.