The young male cat, described as a ginger tom, was found with severe head injuries and surrounded by broken chair legs on Bruce Close in west London, near Ladbroke Grove, at around 9am on Tuesday, September 3.
The damage was so extensive that a vet decided to euthanise the animal to prevent further suffering.
Ellie Barnes-Wilson, an animal rescue officer leading the investigation for the RSPCA, said: "This was a truly distressing discovery for the person who found the cat.
"Signs suggest that he was a victim to serious intentional harm.
"The majority of his injuries were not consistent with a road traffic accident."
The RSPCA has contacted the cat’s owners, who are said to be "absolutely devastated."
Ms Barnes-Wilson said: "This is a heartbreaking case.
"It’s appalling to think that