Written by Doug Wildey (writer and artist)
Released 06/1987
Published in Comico's Jonny Quest Classics #2 - Graphic adventure version of the television episode.In a flashback, the story of how Hadji Singh came to be part of the Quest team as Dr. Quest was looking into a breakout of a strange disease in India and discovers a criminal genius and his underground lab making nerve gas.
Here are the pages I have of it.