In Biggles Nets a Fish, Professor Frail was the director of the atomic research station at Heatherstone Moor. When a packet of micro-films of top secret documents from Heatherstone Moor was found in Germany, Frail, Major Charles and Colonel Barclay consulted Air Commodore Raymond on the aviation angle because the micro-film had been dropped from a plane over Germany. Frail confirmed for Raymond and Biggles that the micro-film has have been photographed by someone working in Heatherstone Moor. It was hard to imagine how anyone else could have gained access.
Throughout Biggles' investigations, Frail was curt and impatient about answering Biggles' questions. He seemed in a hurry to get back to Heatherstone Moor aso that his deputy Doctor Mills could deal with what he called "routine questions". Johns seemed to be setting him up as the villain, but of course, every story must have a twist.