A Dutch meat trader has emerged as a key suspect in Europe's spiralling horse meat scandal following allegations that he was convicted as recently as last year for passing off horse as beef.

Speaking exclusively to the Guardian, Jan Fasen, a director of Draap Trading Ltd, confirmed he bought a consignment of horsemeat from two Romanian abattoirs and sold it to French food processors. He insisted he had clearly labelled it as horse.

But on Wednesday Dutch broadcaster NOS reported that Fasen was sentenced in January 2012 for deliberately marketing South American horsemeat as halal-slaughtered Dutch beef and falsifying documents.

Draap Trading Ltd is a Cypriot-registered company, run from the Antwerp area of Belgium, and owned by an offshore vehicle based in the British Virgin Islands. Draap spelled backwards is the Dutch word for horse.

Despite his denials, the food trader appears to be at the centre of investigations into how horsemeat entered the European food chain. In January 2012 he received a one-year jail term, NOS reported. He allegedly falsified papers to deceive customers. A second Dutch meat trader, from the town of Oosterhout, was given community service, NOS added.

Draap Trading Ltd delivered meat to the French company Spanghero, which in turn supplied another French company, Comigel. The Findus lasagne products found in Britain containing horsemeat came from a Comigel factory in Luxembourg. Spanghero insisted that the meat delivered to its Castelnaudary plant in southern France had arrived labelled "Beef - originating in EU". The company said: "The meat received was beef meat. This was the order that had been placed. Spanghero did not treat or do anything to the meat."

Frozen meat products were, meanwhile, withdrawn from supermarket shelves in the Netherlands, Belgium and France as fears grew that the mislabelling of frozen foods was much more widespread than Findus lasagne in Britain. "It's very much a pan-European issue now." said an EU diplomat.

The Romanians have loudly protested their innocence amid allegations that they supplied horsemeat as beef. Fasen, who bought the Romanian horsemeat and kept it at a cold storage company in Breda in the Netherlands before selling it on to Spanghero, said he would hand over all his information to the Cypriot authorities, who would then pass it on to the French. Dutch food inspectors went to the Breda warehouse on Wednesday.

"As for the Romanian supplies, they delivered 100%," Fasen told the Guardian. "When they deliver beef, they deliver beef. No problem. When they deliver horse, they deliver horse. There is never, ever horse invoiced as beef. I was 100% sure I was buying horse. We sold it to Spanghero in France as well as to clients in Belgium and Holland. It was all sold as horse. There is no issue."

He added: "Somebody made a mistake and it was definitely not us."

The two Romanian slaughterhouses at the centre of the scandal also insisted the horsemeat sent to Holland was properly labelled. Doly Com and Carmolimp confirmed they had sold the horsemeat to Draap. Iulian Cazacut, owner of Doly Com slaughterhouse, said his firm sold over 350 tonnes of horsemeat to the Cyprus company last year, at a price of €2 a kilo.

Cazacut said: "We worked for two years with this Cyprus company. They started buying beef from us a month ago but previously they only bought horse. The problem is not here, it is somewhere out there. We didn't send minced meat. We only sent unprocessed meat."

The scandal has focused attention on the murky pan-European supply chain for meat products, which stretches from abattoirs to supermarkets via mysterious offshore companies.

An investigation by the Organised Crime and Corruption Reporting Project revealed yesterday that that Draap Trading Ltd was registered in 2008 in Limassol, Cyprus. Its sole shareholder is Hermes Guardian Ltd, an offshore company in the British Virgin Islands. A Draap representative, Andreas Mercruri, refused to disclose the beneficial ownership of the company.

Speaking from Cyprus, he told OCCRP: "I'm sorry but with everything that is going on at the moment we are not able to comment on anything at this time." Mercruri answered from the offices of Trident Trust , a Cyprus firm that provides company formation and incorporation services on the island. Trident Trust mentions on its website that beneficial ownership information of the companies it incorporates is not disclosed to any regulatory authority

The same Hermes Guardian company is a shareholder in at least a dozen other Cyprus, Panamanian and Russian based companies.

Cyprus company records indicate a Trident Trust company as a secretary of Draap Trading while its director is another Cyprus company by the name of Guardstand Limited. The latter's paperwork points to a link with Russian business.

Authorities in Romania have suggested that international criminal networks may be involved in the opaque meat trading business. Sorin Minea, head of Romalimenta, the Romanian food industry federation, described France's consumer affairs minister, Benoît Hamon, as an "idiot" after he suggested Romanians may have been responsible for "a case of fraud".

Minea told the Guardian: "There is an international mafia ring behind this problem. I don't know who they may be, or whether any Romanians are involved. But if you think about it, there were five intermediaries so I'm sure that an international network is involved."

He also angrily dismissed the idea that recent European legislation banning horses and carts from Romania's roads had led to a glut of horsemeat: "What was said, that Romania has been slaughtering millions of horses, is a complete aberration. Romania does not have millions of horses at its disposal to slaughter. If we had done that, perhaps we would be better off financially now."

Additional reporting by Roberta Radu and Kim Willsher in Paris

• This article was amended on 14 February 2013. The original referred incorrectly to "the town of Oosterhoutse"; the town is called Oosterhout.