The spokesman claimed that the organisation changed the identify of the horses by substituting their microchips or falsifying animal passports.
Different police actions were simultaneously carried out in France, Portugal, Italy, Romania, Switzerland and the United Kingdom, with the backing of Europol.
Meat from the animals, which came from Portugal and several parts of northern Spain, was processed in a specific facility and from there sent to Belgium, a major horsemeat exporter.
Newspape Público reports the case dates back to 2013 when Irish authorities found horse meat in beef-burgers.
All in all, " seventy-five people have been arrested and prosecuted for crimes such as animal abuse, the production of fakes, or damage to the public health, money laundering and belonging to a criminal association", said Europol in a press release.
In some cases products which were labelled as beef were up to 100 per cent horse meat.
Investigators concluded that the Spanish element of this organisation was a small part of the whole European structure controlled by the Dutch suspect, Europol said in a statement.More news: Trump names special counsel to handle Russian Federation meddling probe
The spokesman explained that officers launched a full-scale probe, called Operation Gazel, after detecting "atypical signs in the horse meat trade" previous year.
This marked the start of an investigation to find the origin of the contamination.
It has emerged Jan Fasen is languishing in jail in Spain after being arrested and extradited from Belgium.
Spanish Civil Guard went public with new details about their involvement in the dismantling of a network suspected of putting horsemeat not apt for human consumption into the food chain and making a staggering POUNDS 20 million-a-year profit.
The investigation eventually led the Civil Guard to the Dutch meat trader, who had initially been involved in the beef burger scandal and was based in Calpe, Spain.
As reported by The Independent, officials have seized the suspects' bank accounts, luxury cars and properties as part of the investigation. Police in Spain began their investigation in 2016 after detecting "unusual behavior" in horsemeat markets.