The Croydon Cat Killer was thought to be an individual who killed, dismembered and decapitated more than 400 cats and various other animals across England, beginning in 2014 in Croydon. Reports of cat deaths attributed to the killer were spread across and around London, and as far north as Manchester. However, in 2018 the Metropolitan Police concluded that the mutilations had not been carried out by a human and were likely caused by wildlife predation or scavenging on cats killed in vehicle collisions.
Some experts, such as Richard Ward, a lecturer and historian of crime and the reporting of crime at the University of Exeter, have stated the view that the Croydon Cat Killer case is an example of a moral panic. In December 2018 a Freedom of Information request detailed that the Metropolitan Police spent over £130,000 and 2,250 hours during their investigation.
In October 2015 South Norwood Animal Rescue and Liberty (SNARL), a small local group of animal welfare activists based in South Norwood, reported incidents of cat mutilation to the police and RSPCA. That November, the Metropolitan Police began to investigate the mutilations, under the name "Operation Takahe" and led by Detective Sergeant Andy Collin.
In January 2016 it was reported that 30,000 local people signed a petition requesting the police conduct DNA testing of the corpses.
By February 2016, the deaths of 10 cats (four in Croydon and one each in Streatham, Mitcham Common, Sutton, Charlton, Peckham and Finchley) had been linked by an examining vet who wished to remain anonymous. However, the police at this time said the number of cases was in single digits In February 2016 it was reported that police had yet to find any evidence that the animals were deliberately killed by a human. At this time an investigating vet stated that he found raw chicken in the stomachs of several killed cats and suggested the animals had probably been lured by the killer with the offer of meat.
In March 2016, Det. Sgt. Collin said that the perpetrator might be only mutilating the corpses after the animals had already died and might only face charges relating to public order or theft. He noted that of the six cases being investigated, five of the cats had not been claimed which would make it difficult to bring charges of theft or criminal damage. As of March 2016, no human DNA had been recovered.
In April 2016 it was reported that the RSPCA believed that the deaths were due to blunt trauma, “likely consistent with being hit by a moving vehicle”. SNARL claimed that the animals were killed deliberately, perhaps by being thrown against a wall. By April 2016, SNARL had recorded 50 attacks across Crystal Palace, Mitcham, Streatham, Peckham, Charlton, Richmond, Orpington, and Farnborough in south London, Finchley, Tottenham and Archway in north London, Stepney in the east, and Guildford in Surrey. SNARL reported that other animals including foxes and rabbits have been attacked in the same way.
In June 2016, SNARL speculated that there had been 100 kills following a decapitated cat being found in Morden. At this time police stated that they had spent 1,020 hours on the inquiry since December 2015.
By July 2016, the media and SNARL had begun referring to the attacker as the "M25 Cat Killer" after new reports, including a cat killed in Whyteleafe, Surrey, suggested the killer was operating around the M25 motorway. After reports of animal deaths in Maidstone, Sevenoaks and seven other locations, SNARL adopted the terms "M25 Animal Killer" and "UK Cat Killer".
Det. Sgt. Collin, speaking in 2017 about a possible motive stated “Cats are targeted because they are associated with the feminine... The killer can't deal with a woman or women who are troubling him”. He added that he was worried that “at some stage he'll escalate or feel brave enough to move on to vulnerable women and girls.” Vince Egan, associate professor of forensic psychology at the University of Nottingham has said: “In some individuals we have seen animal cruelty as part of a broader pattern in which humans are also harmed. It is far more likely that this reflects a rather more banal pattern of anti-social behaviour, such as drunkenness or something that doesn’t go further. But when we have so little to go on you have to keep your mind open.”
In September 2017, ArroGen Veterinary Forensics began re-examining some animals to help the police and RSPCA to bring prosecutions.
In October 2017 it was reported that the killer was suspected of mutilating over 370 animals. Det. Sgt. Collin stated that it was possible there were copycats.
In December 2017, police linked five cat deaths around Northampton from August to November that year to the same killer, but later police stated the Northampton deaths were not being linked to the others though a 31-year-old man had been arrested.
It was reported in August 2018 that, three years after the first report of the Croydon Cat Killer, no evidence relating to an individual who may be committing the alleged crimes had been found. There was no evidence found of clothing, human DNA or a murder weapon and no CCTV footage had been recovered.
In September 2018, the Metropolitan Police reported that in three instances where CCTV footage was obtained, foxes could be seen carrying bodies or body-parts of cats. In one case, CCTV showed a fox carrying a cat's head into a school playground at Catford. In post-mortem examinations conducted by the Head of Veterinary Forensic Pathology at the Royal Veterinary College, fox DNA was found on the cats bodies. The Met closed the investigation on September 20th, saying foxes mutilating the bodies of cats that died in road traffic accidents was the most likely explanation.