It is alleged that a significant number of community cats in the Los Montesinos and the Ayuntamiento area of Spain have been deliberately poisoned notwithstanding that some of them are cats who are part of an apparent TNR program and are therefore spayed or neutered.

The area is as shown on the map below. It appears to be a tourist area on the south coast of Spain. The police are investigating.
A spokesperson for the city administrators said that that there are reports of ‘massive poisoning of cats in specific areas…in recent weeks’.
Mayor Jose Manual Butron said that they are currently in the middle of a sterilisation program and they don’t know who is behind the poisonings.
It is probably a crime as it should be in any decently run country. The city administrator has said that the law treats feral cats in urban areas as domestic cats.
Comment
It seems likely that there is a battle going on over how to deal with the feral cats, better described as community cats as these cats are probably fed by tourists and residents. Although I am told in a forum that it is illegal to feed feral cats in this part of Spain (this may clash with the statement above about treating feral cats as domestic cats).
There are those who want to deal with community cats decently which means operating a TNR program to manage breeding and bring down numbers and those who neither have the patience nor the decency to treat the cats humanely and want to kill them. You then arrive at the scenario as described: TNR cats being killed randomly with poisoned food I suspect.
But I must be cautious and say that at this stage this an allegation of deliberate poisoning. There may be other factors at play. If it is true, it is not untypical of the attitudes of a small minority of residents in many countries including America.
Although, it must be said that America is the leading country for running TNR programs and dealing with feral cats humanely despite hostility by some cat haters.
Source: Costa Blanca and Costa Calida Leader online newspaper.