A flock of sheep grazing on a snow-covered Welsh fieldLibrary photo © Graham M Lawrence/ INP/Rex/Shutterstock

The remains of up to 20 butchered sheep carcasses and their fleeces have been illegally dumped by a river in north Wales.

Police say illegal butchering and theft were probably to blame for the dumping of sheep body parts at the Dwyryd estuary, near Maentwrog, Gwynedd.

Some of the remains were left in the open air; others were in black bin bags.

See also: ‘Meat thieves’ butcher sheep to death in field

Ear tags had been removed from the animals, making it difficult to trace the owner.

The North Wales rural police team appealed for help to find the offenders after the incident came to light on Thursday (29 December).

It said: “We need to know who is responsible.”

Anyone with information about the incident is asked to call police on 101.

Strict rules govern the slaughter of animals – whether or not for human consumption.

Business operators must meet legislative requirements in terms of slaughterhouse design, layout and equipment.

Individuals carrying out certain slaughter operations must hold a certificate of competence for the operations they perform.

There have been a number of instances of illegal slaughtering in recent years – sometimes involving animals being killed and butchered in fields.

In October, farmers were warned to be on their guard after a flock of sheep was taken from a farm in Renfrewshire, Scotland.

Police said they feared any meat from the sheep could pose a health hazard – warning that those responsible for stealing the animals could slaughter them illegally.