In The Case of the Old Masters, Baron Wolfner was a noted Hungarian art critic who was well-known in Art circles. He organised the theft of valuable paintings from galleries and had them flown out of the country with marine aircraft, using his house, Frantham Old Hall, on the Suffolk coast as a base. What gave him away was the pieces of paper he scattered over the water in the creek by his house. Biggles and Ginger spotted them from the air and remembered that this was a device used to help trainee marine pilots judge the surface of dead calm water. Since paper could not float in the water for very long, their deployment must mean that a marine aircraft was scheduled to arrive very soon.
Biggles laid an ambush for the marine aircraft and arrested the Baron as he was walking to meet the plane while carrying a parcel of paintings. The Baron dropped the parcel and ran, firing at Biggles at the same time. Biggles, however, overpowered and handcuffed him. He was handed over to Inspector Gaskin and it is presumed that he was subsequently prosecuted.