Investigators appear to have finally unraveled one of the tangled threads of mislabeling in Europe’s food supply system that led to horse labeled as beef ending up in nearly 4.5 million food products.

The first loose thread was exposed by Ireland’s Food Standards agency, which said that burgers in several supermarket chains contained horse. The agency alerted U.K. regulators, which in turn ordered companies to test beef products for horse. This exposed more mislabeled products, this time made by French firm Comigel.

The Comigel horsemeat was traced back to Romanian slaughterhouses, where it was apparently sold correctly labeled via third-party traders to French food firm Spanghero.

French investigators say Spanghero then knowingly sold the meat mislabeled as beef to Tavola, a contractor Comigel, which makes frozen meals for supermarkets and other firms at a plant in Luxembourg.

Comigel products using the meat were then sold to 28 companies in 13 European countries.

(paulkerry@heraldcorp.com)