The boyfriend of a missing British hiker claims she was likely taken “against her will” when she vanished on a hike in the Pyrenees in Spain.

Dan Colegate, 38, said he believes the “terrifying prospect” that “somebody else was involved” in the disappearance of his girlfriend, Esther Dingley, 37, BBC reported.

“A happy, experienced, well-equipped and fit young woman went missing in an area with clear paths and mostly open terrain,” he wrote on Facebook.

“An intensive search found no sign of her, or any of her equipment. It is as though she vanished into thin air.”

Dingley was last seen on Nov, 22 during a solo trek to the summit of Pic de Sauveguard, a mountain between Spain and France.

Another hiker who encountered her on the trail said Dingley appeared to be emotional and had talked about experiencing relationship problems.

“Esther said she and Dan were taking a break and she didn’t know if they were going to get back together,” Laura Adomaitye said, the Sun reported.

“When you are not 100 percent OK with your partner, you’re not going to be totally balanced emotionally.”

But Colegate shot down any suggestions that there was trouble in their relationship as “salacious nonsense.”

“For almost two decades now we have shared almost everything, building a life together that was occasionally challenging but mostly full of joy and love,” he said.

Search crews have found no trace of the missing hiker, while authorities investigating her disappearance said they haven’t ruled out that it was “non-accidental,” BBC reported.

Colegate, who is currently in France, said he’s sure that if she was injured in the mountains, she would have been found by the search crews.

“All of which leads me to believe that somebody else has been involved in Esther’s disappearance and against her will,” he said.

“This is a terrifying prospect and I wish I could believe otherwise, but I cannot.”