A man has been arrested over a series of cat killings in Northampton as police investigate whether the attacks are linked to those in Croydon.
Five dead felines were found mutilated in Northampton between August and November last year.
The 31-year-old suspect has been released under investigation.
Officers are trying to work out whether the deaths, in the Duston and Kingsley Park areas, are connected to the so-called Croydon cat killer.
Northamptonshire Police said it was working closely with the Metropolitan force, whose investigation is known as Operation Takahe.
While the attacks are similar to those in London, officers remain unsure whether they were carried out by the same person.
A group which has been helping police with the inquiry, and cataloguing the attacks, said it did not believe the arrested man was the culprit.
“The killer has not been caught,” said South Norwood Animal Rescue and Liberty (Snarl) co-founder Boudicca Rising.
Nevertheless, Ms Rising believes the most recent killings could be useful to the investigation.
“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.”
Attacks over the festive period were reported in south London, north London, Aylesbury and Tunbridge Wells.
Snarl believes that up to 400 cats and other small animals may have been slaughtered across the country.
It is thought the killings began in the south London area in around October 2015, leading to the attacker being dubbed the Croydon cat killer.
However other small animals, such as rabbits and foxes, have also been found dead and mutilated across the country.
A £10,000 reward is on offer to anyone with information that could lead to the killer’s arrest.