A person dubbed the "Cat Ripper of Croydon" is believed to have killed more than 30 cats in that area of south London, United Kingdom, over the past two years.
Animal rights organisation Peta has offered a £5,000 (S$10,200) reward for any information that could lead to the person's arrest.
A member of British pop band The Vamps has also offered free tour tickets to help catch the culprit.
Some of the animals were decapitated, while others were disembowelled, Sky News reported on Wednesday (Jan 27).
The Mirror said that other cats were mutilated in different ways, including one that had its leg cut off.
The Mirror also reported that pet owners were finding their cats' body parts, distressing them terribly.
British celebrities like former X Factor host Dermot O'Leary have used their profile to spread the word about the "Cat Ripper", retweeting appeals for information about the killer.
"We're grateful to these compassionate stars for alerting their millions of fans about this sickening case," Peta's associate director Elisa Allen said.
The organisation added that residents should keep an eye on their cats and not let them outdoors until the killer is caught.
The killings echo those of cats in Yishun, where at least 20 cats have been found dead since September last year. Two men have been arrested in connection with the cases.