The body was discovered yesterday (August 30) evening in a "neighbour's garden" while his owners were away on holiday.
The incident has now been included in the Metropolitan Police's investigation into the serial animal killer.
On the same day, the charity reported incidents in Ewell and Aylesbury.
Tony Jenkins, co-founder of South Norwood Animal Rescue and Liberty (SNARL), the charity leading the efforts to bring the killer to justice, told getwestlondon : "The cat was taken to a vet and they contacted me.
"I went and examined the body and it matches previous cases."
The owners have been informed of the incident but, according to Mr Jenkins, they still don't the "nature" of their cat's death.
Mr Jenkins has confirmed that further information about the case will be released "at some point" after the owners return to the country.
Around 300 animals - including cats, rabbits and even a squirrel - have been killed and mutilated since October 2015, the group said.
The first victims of the UK Cat Killer were found in Croydon in 2015, but since then bodies have been found across parts of southern England, including west London.
In December 2016, a dead cat with its "tailed chopped off" was found in Feltham and, earlier this year, an animal was mutilated in Ruislip .
Mr Jenkins said animals are often killed by blunt force trauma.
"I personally think it is an attack on humans, they make displays," he said.
"It is disturbing families, they might have young children.
"This person cuts the head off and puts it on display and he is doing the same with foxes.
"He puts them near schools or children playgrounds.
"This is an attack to horrify and disgust humans."
The first description of the suspect was released on Saturday (August 26).
The charity wrote on their Facebook page: "Just a reminder that the suspect is a white male with dark brown hair, in his forties, with a pock marked or scarred face.
"He has no discernible accent.
"He has been seen at a number of locations with variously, a head lamp, a torch, a backpack and a large man bag, approaching cats with food and toys and making 'kissing noises'."
Facebook users have expressed concern over the killings, with one saying "there is no way that once caught and failed, this runt should ever be allowed to see the light of the day again for his entire life."
The charity has urged anyone with information about mutilated or dead animals to contact the police on 101 and report under Operation Takahe.
In addition, the group is offering a £10,000 reward, along with animal rights groups PETA and Outpaced,
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