In Biggles Hunts Big Game, Colonel Dupray was an Indian Army officer who joined the Hunters' Tour operated by Stellar Skyways, the airline operated by the counterfeiting gang headed by Kravas. Dupray was on the same flight as Ginger and Bertie from Cairo to the hunting-lodge at Kudinga. Ginger and Bertie were travelling undercover, by coincidence, also as officers of the Indian Army. Ginger observed that Dupray was an elderly, robust man with a sun-tanned skin, dressed in well-worn tweeds and "as characteristic of a Britisher of the sporting type as would be possible to imagine."
Later in the plot, when Ginger complained to the lodge manager, Mr Kreeze, that his bags had been tampered with and his radio transmitter had been removed, he had to give the a plausible reason for having the device in the first place. He told Kreeze that a new regulation required Indian army officers on leave outside India and Britain to remain in contact with headquarters. While plausible enough, the explanation was unfortunately debunked by Dupray later. Kreeze had asked Dupray about it and Dupray told him there was no such regulation. He was on the General Headquarters staff and any such regulation would have to pass through his office. Dupray thus effectively blew Ginger and Bertie's cover.
Dupray took no further part in the plot. It can be assumed that during the events leading up to the police raid on Kudinga, he must have been away on a beat to a distant part of the hunting grounds.