More than 400 animals, mainly cats and dogs, have been rescued from a trafficking network in Spain.
The gang is suspected of illegally importing animals into Spain from eastern Europe via Andorra before selling them on to make a profit.
They have also been accused of forging documents to say the animals were healthy for sale when they weren’t.
Thirteen people have been arrested on charges including animal abuse, fraud and money laundering.
The animals, which were often kept in poor conditions, have since been receiving care from vets.
The joint police operation to recover them took place in September – three years after officers in Barcelona received several complaints about the poor conditions at a pet shop in the city’s centre and found 33 sick dogs there.
The authorities said on Wednesday that some of the recovered animals, which were often breeds with high market value, were illegally bought online.
Others were bred in centres that the suspects ran, where female animals were used to produce as many offspring as possible without care for their health.
Many of the animals were then transported by road, often in cramped and unsanitary conditions, on long trips that sometimes covered more than 2,000km (1,242 miles).
This led to some developing infectious and contagious diseases, which then spread to other animals they were being sold alongside.
“The criminal organisation included a veterinarian who provided her knowledge and signature in order to give an image of sufficient reliability with which to guarantee that the animals sold were in good condition,” said the authorities in a statement.
They added that the vet advised others in the criminal organisation on how to hide or disguise records during official controls and inspections.
Spain last month passed a law tightening up the rules governing the sale and ownership of animals. This includes banning their sale in pet stores and violations can mean jail time or fines up to 200,000 euros (£173,000).
