Police are investigating whether foul play was involved in the deaths of six dogs found in two boxes in a Yuen Long village yesterday.
About five kilometres away, another five mongrels were found dead at an open-air storage centre over the weekend.
There was no indication to suggest that the two cases were linked, a police investigator said.
The carcasses of the six mongrels were discovered by a cleaner, 40, at a rubbish collection centre outside Wing Ning Tsuen on Yung Yuen Road at about 9.30am.
"Initial examination showed the dogs had no obvious signs of injury," a spokeswoman for the Society for the Prevention of Cruelty to Animals said. "Blood was found in the mouths of two of the dogs, suggesting both had vomited blood or suffered internal bleeding."
She said it was unusual for so many dog carcasses to be found at one site. She believed the animals had died elsewhere and were moved to the refuse collection centre for disposal.
SPCA vets will work with police to find out the cause of death. The Agriculture, Fisheries and Conservation Department will also carry out toxicology tests.
A police spokesman said officers searched the area, but no poison bait was found.
He said the deaths were classified as cruelty to animals and detectives from Yuen Long were investigating. No one has been arrested.
The SPCA said all of the six were adult female dogs. Only one carried an identification microchip issued by the department. The other five were unregistered.
The spokeswoman urged dog owners to watch over their pets and to send their animals to have microchips implanted.
The other five dead dogs were found on Yick Yuen Road, Lau Fau Shan.
The police investigator said no evidence suggested they had died from poisoning. "We are waiting for the results of toxicology tests," he said.