According to the GNR, the four Irish men were part of a group of six men arrested on 3 and 14 February by the Setúbal Territorial Command.

The gang of men would provide tarmacking services at a reduced cost, using surplus tarmac from previous jobs, saying they would do the work for the cost of the labour alone.

According to the GNR, once the deal was made, the men would charge a much higher fee than had been agreed.