In The Case of the Sabotaged Parachute, Len Betts was the son of Flight Sergeant Betts, a retired R.A.F. serviceman turned dog breeder who kept an establishment at Dell Farm, near Sway in the New Forest area. While out in the woods, Len found a parachute and brought it to his father. His father saw that the parachute cords had been cut and suspected there was some foul play and called Scotland Yard. Len told Biggles and Gaskin he had also seen a man in the area who seemed to be looking for something. Len subsequently assisted Biggles and Gaskin in a sweep of the surrounding area, handling an Alsatian tracker dog loaned by his father. While following the dog, he came across the man whom he had spotted earlier. Later, the dog discovered the the body of the French fugitive Raoul Dubroc. This, and the identification of the man Len had encountered in the woods as the gang leader Louis Brand, led eventually to the destruction of the entire gang. As Biggles told Marcel after the case, it was Len's good sense of reporting the find to his father which started the entire chain of events which ultimately led to a satisfactory outcome.