A man has been arrested over a string of cat killings in Northampton as police continue to investigate whether the attacks are linked to the so-called Croydon cat killer. But a charity working in cat protection has played down the significance of the arrest.

The 31-year-old man was held after five cats were found dead and mutilated in the town between August and November last year.

Northamptonshire police said the suspect, who was arrested in connection with arson attacks and cat mutilations in the Duston and Kingsley Park areas, had been released under investigation.

The force confirmed it was working closely with the Metropolitan police inquiry into a number of animal deaths, known as Operation Takahe.

But it said that although the offences were similar to attacks in the London area, officers were not sure that they had been carried out by the same person.

South Norwood Animal Rescue and Liberty (Snarl), which has been cataloguing the deaths and helping police with the investigation, has said it does not believe that the person arrested was behind the killings and warned pet owners that their animals were still not safe.

The group believes up to 400 cats and other small animals may have been slaughtered across the country by at least one culprit, who has also been labelled the M25 cat killer and the UK animal killer.

In a statement on its Facebook page, Snarl said: “The person or persons known as the UK animal killer remains active and we continue to attend incidents, the latest one yesterday.”

Over the festive period there was a string of reported attacks in south London, north London, Aylesbury in Buckinghamshire, and Tunbridge Wells in Kent.

Snarl’s co-founder, Boudicca Rising, said that she believed the most recent spate of attacks could hold the key to catching the killer.

“What is really clear from the timeline over Christmas is that he was in south London and then started travelling again,” she said. “We have always thought he is a south London resident. He seemed at ease with getting around and the killings seemed more confident.”

The attacker was first labelled the Croydon cat killer because it is believed the killings started in the south London area in about October 2015.

But small animals, including rabbits and foxes, have since been found dead and mutilated across the country.

In an interview with the Observer in 2016, Rising said she believed the killings were the work of the same person. “They are mostly bodies with the heads, or heads and tails, removed.”

The same year the RSPCA also investigated some of the cat killings believed to have been the work of the Croydon cat killer. It said an examination of the bodies by its vets suggested that the cats’ heads and tails appeared to have been removed by a human.

The Met has been working with the RSPCA and Snarl, while a £10,000 reward has been offered to anyone who provides information that could lead to the arrest of the killer.