Who or what is killing hundreds of cats at Saint-Pierre-la-Mer near Narbonne in South East France?
Since June, locals have sighted cats who vomit a blue substance, miaow piteously, then die.
The symptoms, and the confinement of the problem to a small area, were both suggestive of poisoning, and local animal welfare organisations were quick to blame traces of rat poison, motor oil and even cannabis found in samples of cat food.
However, tests on two of the dead cats conducted in laboratories in Lyon seem to have isolated a different cause.
Following tests, it seems likely that the deaths have been caused by a feline calicivirus. This is a virus affecting cats, which is often harmless, but can also cause a rapidly-spreading epidemic, with mortality rates of up to 67%.
The fact that the infection has not spread beyond the initial area of infection has caused some to doubt the diagnosis.
The southern French coast sees a surge in the population of street cats over the summer months, when many holiday-makers abandon their pets by the side of the road. Authorities are braced to deal with the rescue and sterilisation of these animals, as well as a possible spread of the calicivirus.