In Biggles Foreign Legionnaire, Nestor Janescu was one of the "Committee of Three", the three top financiers who controlled the war-mongering syndicate from behind the scenes. A Greek oil magnate who normally lived on board his luxury yacht Silvanus at Cannes, Janescu was one of the names on a list which Air Commodore Raymond had drawn up of people who might be linked to the war-mongering syndicate. In Chapter 8, Biggles and Ginger had infiltrated the war-mongering syndicate and were about to be sent to Alexandria. Algy, who had come to Zebrit to help told Biggles that Janescu had arrived at Alexandria on board his yacht.
Biggles never met Janescu. At Maison Blanche Airport on the way to Alexandria, he read a newspaper article which reported that Janescu had been murdered by an unknown assassin. This piece of news seemed to affect Biggles' traveling companion, the syndicate operations manager Johann Klutz greatly, confirming for Biggles that Janescu was indeed behind the syndicate.
Later in Alexandria, Biggles and Ginger discovered that Janescu's killer was Cy Lindsay, an American ex-syndicate member with a personal grudge against the group and out to kill as many of its top leaders as he could.