Scotland Yard spent a total of £8,100 carrying out post-mortem examinations on cats who were believed to be victims of the so-called Croydon cat killer.
The three-year investigation, called 'Operation Takahe', looked into the deaths of hundreds of cats who were decapitated and dismembered across the London borough of Croydon since November 2015.
The case was closed earlier this year after police concluded that foxes were responsible for the killings.
- Read more: Croydon Cat Killer mutilations were a fox, says Scotland Yard
- Read more: Woman cleared after stabbing dog to death for attacking cat
Responding to an FOI request from talkRADIO, the Metropolitan Police Service revealed that £6,000 had been spent on post-mortem examinations in 2016, with £800 spent on re-examination of the post-mortems this year, and a further £1,300 spent on microscopic hair testing.
Post-mortem examinations on an initial 25 cats showed that they died of a blunt force trauma, such as being run over. Their bodies were believed to have been mutilated after they had died.
Just six cases were deemed to be suspicious and required further investigation.
'No evidence of human involvement'
The Met have estimated that 2,250 police hours were used on Operation Takahe, with two detectives and two constables working on the case at one stage.
In a statement in September, Scotland Yard said: "No evidence of human involvement was found in any of the reported cases. There were no witnesses, no identifiable patterns and no forensic leads that pointed to human involvement.
"Witness statements were taken, but no suspect was identified."
'The stuff of nightmares'
Martin Clunes. Image: Getty
Actor Martin Clunes - who went to school in Croydon - wrote a letter to detectives in 2016, calling the case "the stuff of nightmares".
"I read with horror that some of the cats had been decapitated and dismembered - this is the stuff of nightmares," he wrote.
"The local community is understandably distraught and frightened. No-one feels safe while this sick individual is on the loose."