Police probing alleged unauthorised vaccine camps in Sonarpur said the serial numbers on the vials found in possession of the accused, Mithun Mandal, had matched those on Covishield vials in batches sent to Diamond Harbour for use in the official drive.

This means the liquid administered in the alleged unauthorised camps could be Covishield, which Mandal, a pharmacist at a primary health centre in Diamond Harbour, seems to have removed from the official stocks in an unauthorised manner.

Police are awaiting a final forensic report on the composition of the liquid found in the seized vials.

“Our preliminary investigation and inputs from the state health department suggest that the batch numbers and serial numbers of the vials seized from the accused have matched the stock details of the officially despatched Covishield vials. For further confirmation we are awaiting the forensic report on the liquid in the vials,” said a senior police officer.

An official in the health department said Mandal had misused his position to steal vials and then entered the details of the people whom he administered the vaccine on the CoWIN portal. Those who were administered the liquid at Mandal’s camps, which he held in people’s homes, got vaccination certificates from CoWIN.

“Mandal had direct access to vaccines and was also in charge of data entry in CoWIN. He thus misused his position,” said an officer.

The health department official said Mandal could exploit his position and steal vials because of shortage of staff in primary health centres in remote areas.

The Diamond Harbour subdivision has 11 primary health centres and 184 vaccination centres.

“It is a known fact that we do not have adequate staff at remote health centres. Usually, the responsibility of handling vaccines and data entry in the portal is shouldered by two or three employees. At times even one person has to do everything,” said a health official in the South 24-Parganas district administration.

Mandal, who has been remanded in police custody, has purportedly told the police that he had administered the liquid to not more than 30 or 40 people.

Police sources said at least five health department employees were examined on Sunday.

“Mandal might not be the only one involved in this," said an officer of Sonarpur police station.

A police team took Mandal to several locations in Diamond Harbour on Sunday, apparently to try and ascertain the sequence of events.