The dogs' bodies were found by a walker

The RSPCA described the killer as "callous and cowardly" after the animals were found by a walker late on Sunday as she walked over remote moorland near Bridgend.

Officials said they were mystified by the unnecessary deaths of the dogs.

They were discovered in a stream on moorland outside the village of Tondu where the nearest road address is Ffordd-y-Gyfriath.

It is shocking to come across animals dumped in this way RSPCA

One was a tan coloured cross-breed bitch which had masking tape wound tightly round its muzzle.

The second dog was a black and white cross-breed which still had masking tape around one paw and was thought to have been fully bound when dumped.

"We are mystified as to why these animals ended up on top of this isolated moor in a stream," an RSPCA spokeswoman said.

"They were both in fairly good condition with no blood on their bodies and no obvious signs of death.

"It is shocking to come across animals dumped in this way and there is absolutely no reason for it to happen.

"This was a callous and cowardly dumping of two dogs at Christmas time.

"Anyone could have handed over the animals to an agency like the RSPCA without doing this."

The RSPCA said it had no idea how or why they had died.

The bodies of both animals have been taken to a local vet`s to try to establish the cause of death.

The spokeswoman appealed to anyone with any information to contact the RSPCA on 08705 555999.