In The Case of the Black Sheep, Louis Vanberger was a wool merchant of Louis Vanberger & Co. of Glasgow. In his business, he received regular shipments of black St. Kilda's wool from Flight Lieutenant R. Q. Paullson who keep a sheep farm on island of Lagganmalloch in the Hebrides. When Vanberger found that Paullson used a seaplane for communicating with the mainland, he approached Paullson and asked him to use the seaplane to fetch a few parcels from the sea for him. These parcels had been thrown overboard the ship Sirocco by an accomplice of Vanberger and contained valuable quantities of contraband nylons. Paullson would fetch these parcels and then ship them to Vanberger concealed in bales of wool.
Vanberger did not reveal the true contents of the parcels to Paullson. He merely hinted that helping in this racket was a way for Paullson to get more American cigarettes, which he liked. To keep up the illusion, Vanberger never paid Paullson any money for his services, merely supplying him with cigarettes as a reward.
When Biggles cracked the case and uncovered the details of the racket, he convinced Paullson to turn King's Evidence against Vanberger. Although it is not mentioned in the story, it is likely that Vanberger received a stiff sentence for his crime.