Spanish authorities are investigating the recent deaths by poisoning of more than a dozen dogs in Lérida, a city in the northeastern region of Catalonia that has become ground zero in an intensifying debate over the role of Islam in Spain.

All of the dogs were poisoned in September (local media reports here, here, here, here and here) in Lérida's working class neighbourhoods of Cappont and La Bordeta, districts that are heavily populated by Muslim immigrants and where many dogs have been killed in recent years.

Local residents say Muslim immigrants killed the dogs because according to Islamic teaching dogs are "unclean" animals.

Over the past several months, residents taking their dogs for walks have been harassed by Muslim immigrants opposed to seeing the animals in public. Muslims have also launched a number of anti-dog campaigns on Islamic websites and blogs based in Spain.

In response to the "lack of sufficient police to protect the neighbourhood," 50 local residents have established alternating six-person citizen patrols to escort people walking their dogs.

In July, two Islamic groups based in Lérida asked city officials to regulate the presence of dogs in public spaces so they do not "offend Muslims." Muslims are demanding that dogs be banned from all forms of public transportation including all city buses as well as from all areas frequented by Muslim immigrants.

Muslims in Lérida say the presence of dogs violates their religious freedom and their right to live according to Islamic principles.