In Biggles in de jungle (Vandersteen comic), Jennifer Harland was the fiancee of American explorer Eddie Roberts. When Eddie and his father Charles were captured by "The Tiger", a bandit chief in the jungles of British Honduras, Jennifer attempted to make contact with him to negotiate for their release.
Biggles first encountered her in Mexico City. Jennifer had been attacked by a gang of toughs (who later turned out to be the Tiger's men). Thereafter, she disappeared. It was in tracking her down that Biggles would end up in British Honduras and get involved in hunting for "The Tiger". Throughout her efforts to help her fiance, she preferred to play a lone game, to the extent that Biggles was not sure whether she was a friend or an enemy. She took extreme measures to conceal her identity, she stowed-away in Biggles' aircraft and most spectacularly of all, she held up Biggles at gunpoint and foiled his attempt to arrest the Tiger.
Jennifer later explained to Biggles that she had to do all this and act alone so as not to endanger the lives of Eddie and his father. Later, however, she realised that the best option was team up with Biggles and she sought his help to release Eddie from the panther's cage.
The character of Jennifer Harland only appears in the Vandersteen comic strip and not in the original Johns novel.