A grisly discovery of four dead swans in the River Nene at the Embankment in Wellingborough is being investigated by Northants Police.
The four Mute swans' bodies were discovered close to the Whitworth's Mill section of the river and have been reported to the authorities.
A widely shared video on social media alleged that at least one of the swans had been decapitated.
Members of the Wellingborough Police and Northants Rural Crime Team are leading the investigation.
In a neighbourhood alert they said: "Wellingborough Police and Northants Rural Crime Team are investigating the death of a number of swans on the River Nene at The Embankment.
"This is believed to have happened between Monday, November 22 and Tuesday, November 23, 2021.
"If you have any information which could assist us with our enquiries please call 101 and quote 21000683009. Thank you."
Neighbourhood Policing Sergeant Gina O’Connor-Frisby, said: “I know there is concern in the local community regarding the death of these swans and we are working with our partners at the RSPCA and North Northants Council to ascertain how they were killed.
“In the meantime, members of the public are welcome to approach our neighbourhood officers in the local area if they have any concerns or information they wish to pass on.”
A spokesman for Northants Police added: "There were four swans and we believe it was deliberate."
No mention of the River Nene in the weekly findings of highly pathogenic avian influenza (bird flu) in wild birds in Great Britain have been reported by Defra (The Department for Environment, Food and Rural Affairs).
Responding to a claim on social media that wild swimmers have been told to avoid swimming in the Nene, a UK Health Security Agency spokesman said: "Avian influenza is primarily a disease of birds and the risk to the general public’s health is very low."
The latest guidance and news can be found here https://www.gov.uk/guidance/avian-influenza-bird-flu