Esther Dingley and Dan Colegate had been travelling all through Europe since 2014.
The 37-year-old Oxford graduate set out on a solo hike from the Port de la Glere to the Port de Venasque, a trek which follows the border between France and Spain, based on native police.
She was final seen on November 22 and was anticipated to return on December 2.
Captain Jean-Marc Bordinaro of France’s Gendarmerie de Saint-Gaudens advised The Instances: “Esther Dingley needed to proceed along with her present lifestyle, journeys in a camper van and sporting actions together with mountain climbing, while Daniel Colegate appears a bit bored with this nomadic life.”
He added: “Did Esther Dingley need to go off on her personal to stay her life and organise her personal disappearance? There’s nothing enabling us to eradicate this working principle.”
Captain Bordinaro advised the Each day Telegraph: “It might have been an accident, it might have been voluntary disappearance or a legal act. We simply don’t know so are pursuing all of those traces for now.”
Authorities in France and Spain have needed to name off searches of mountains the place she was final seen as a consequence of heavy snow.
Mr Colegate, 38, has been interviewed by police thrice by officers accumulating background details about her. He isn’t thought-about a suspect.
A spokesman for lacking individuals charity LBT International, which is aiding her companion stated “there’s completely no suggestion that (Ms Dingley) was searching for ‘one other life’”.
Mr Colegate stated in a Fb put up on December 1 that the “prevailing opinion” of authorities was Ms Dingley was not within the mountains following intensive searches.
She is now listed as a nationwide lacking particular person in Spain and her case has been handed to “a specialised judicial unit in France”, he added.
“As issues stand tonight, Esther is now listed as a nationwide lacking individuals case in Spain and the case has been handed to a specialised judicial unit in France.
“This implies they are going to be taking a look at different choices past a mountain accident.”
Mr Colegate stated he was “very grateful” for the intensive efforts of rescue groups in Spain and France, which had utilised helicopters, canine and a drone.
“Whereas this can be a terrifying growth in some ways, I’m making an attempt to concentrate on the truth that it leaves the door open that Esther would possibly nonetheless come dwelling,” he stated within the put up.
“She was so totally completely happy and joyful after we final spoke, I’d do something to see her face and maintain her proper now.”
The couple, from Durham, began to journey after Mr Colegate had a severe well being scare, and had been documenting their campervan adventures on-line.
A International, Commonwealth and Growth Workplace spokesman has beforehand stated its employees have been “supporting the household of a British girl reported lacking within the Pyrenees and are in touch with the French and Spanish authorities”.