Bardello had been an air gunner in the RAF during the Second World War and had served in the same squadron under Crayford. After his discharge, Bardello had drifted into a life of crime and joined a gang of car bandits. After a mail-van robbery, Bardello double-crossed his gang and fled with the loot. Knowing that he would be pursued ruthlessly, he had gone to Holmwood Flying Club hoping to steal an aircraft. There he had met, by chance, his old squadron-mate Crayford and persuaded him to give him a joyride for old times sake. Although Crayford had told him that he was not qualified to take passengers, Bardello had somehow coaxed Crayford into agreeing.
While in flight, Bardello had hit Crayford on the back of the head, killing him. He had then taken the aircraft, a De Havilland Tiger Moth towards the south of France. When his fuel was exhausted near the town of Provins south of Paris, he had landed in a field and then faked a crash by running the plane into a tree.
Called by Marcel to examine Crayford's wreckage, Biggles was able to deduce the main facts from the state of the aircraft. Enquiries at the local station revealed that a foreigner had bought a ticket of Nice just after the time the crash was believed to have occurred. Armed with this information and a description of Bardello from the station master, Marcel and Biggles flew on to Nice, arriving ahead of the train and then apprehended Bardello as he disembarked. He was caught with the proceeds of the mail robbery and his fingerprints were found in the rear cockpit of the Tiger Moth. Bardello was extradited, tried and subsequently hanged for the murder of Crayford.