A special group formed with the sleuths of police and CID collected fingerprints from the spot and sent them to the State Forensic Laboratory.

The investigating officers suspect the involvement of professional killers in the case.

Also, the piece of clothing found in the sack along with the body parts turned out to be a red herring.

“It looks like the blouse inside the sack was planted to misguide us. So far we have interrogated a couple of women who were known to Gupta, but their involvement could not be established. The investigation is on,” said an officer.

The police also have not determined the motives behind the murder. It was learnt that among those grilled by the team were two of his colleagues and an LIC agent (all women).

While examining the call list of his lost mobile phone, and the personal computer and diaries, police got three names — Manju Kunthia, Kamini and Kanchan — but they have not been traced so far, the police added.

“We are investigating the matter from all possible angles, but yet to come across any concrete clue,” said Basab Dasgupta, Additional Superintendent of Police, Barrackpore.

The police and CID have interrogated the residents of Metal Road, near the Bilkanda-Muragacha area where the body was found on Monday. They told the police that they had heard dogs barking around 3 pm the previous day near the nallah where the body was found. The locals added they did not not hear the sound of any vehicle.