Detectives investigating the so-called Croydon Cat Killer believe they have found the culprit - and it comes from within the animal kingdom.
Scotland Yard said its three-year investigation, which saw dozens of slain animals examined, has concluded humans are unlikely to have been responsible for killings.
Instead, a fox or foxes are believed to be behind the mutilations in south London.
Police said forensic tests and post-mortem examinations were carried out on several carcasses and pointed to foxes' involvement.
On Thursday, police in Croydon set out the investigation's final conclusion that there is no evidence of human involvement.
All of the cases of cat mutilation will be recorded as "no crime", a Metropolitan Police spokesman said.
Frontline policing commander Amanda Pearson said: "The decision was made to allocate a large number of similar reports of mutilated cats to the officers who were investigating the initial spate of such allegations.
"While this increased the workload of those officers, it significantly reduced the resources that would have been required for different officers in different units to record and assess each allegation separately.
"It is this collating of reports that enabled officers to work with experts and reach the conclusion that no further police investigations are required into any of the allegations relating to mutilated cats."
Story by Press Association