In Biggles and the Blue Moon, Sosbell was the name of one of three American bandits who planned to seize the pearl collection of Lin Seng. Together with fellow gang members Cortello and Sam, the three had set up camp in the jungles surrounding Taihan, the remote countryside villa belonging to Lin Seng. By controlling the only access road and cutting off the telephone line, they laid siege to Taihan and warned Lin Seng that he would only be allowed to leave the location if he left his pearls behind.
Biggles first met Sosbell at the "Teahouse of the Golden Flower", in a village near the junction where the access road to Taihan met the main road. Biggles was surprised and a little suspicious that Sosbell did not exchange greetings at their arrival, something which travellers to a remote location might naturally do. In addition, the local police sergeant told Biggles that Sosbell had stayed at the teahouse some two-three weeks but did not talk much and nobody seemed to know what he was doing.
When Biggles sought to leave Taihan in order to collect his Auster to fetch Lin Seng, the bandits who were controlling the access road ambushed his vehicle and took him prisoner. Thus Biggles met Sosbell the second time. It was Sosbell who did most of the talking, angrily demanding where Biggles had hidden the pearls, and finding none after searching the car thoroughly.
The gang soon began to fall out with one another. First, Sosbell was upset with Cortello because he had not bothered to pass on information which Biggles had earlier given about the approach of hostile Indonesian commandoes intent of seizing Taihan and its pearls. Later, when Cortello wanted to go nearer to Taihan to scout out what was happening there, Sosbell, not trusting Cortello, sent Sam to shadow him.
Sam saw Cortello crossing into the Taihan golf course by means of a fallen tree which spanned the crocodile infested gulley which divided the jungle and the Taihan compound. When Sam saw Cortello talking to Algy, he believed Cortello was double-crossing the gang and so Sam murdered him. Sosbell then decided to do his own reconnaissance of Taihan by going to the fallen tree. In order to keep the group together, they brought Biggles along. The scouting expedition however came to an abrupt end. Algy, not knowing the others were around, decided to blow up the fallen tree with dynamite to improve security at Taihan. The blast caught Sosbell and his partners by surprise, killing or stunning most of the party. After Biggles recovered, he found Sosbell on the ground next to him. Biggles retrieved his gun from Sosbell's pocket and made his escape. Sosbell was never seen again. If he had died in the explosion, his body was not found to confirm it. It was thought possible that his body had been devoured by the crocodiles which lived in the gulley.