The death of British hiker Esther Dingley remains a mystery to detectives who are keeping all options on the table in their investigation.

A skull with hair attached was found in the Pyrenees mountains and yesterday DNA results confirmed it as hers.

It ended a months-long search for the Durham-born walker, 37, who was last seen setting off on a solo journey in November.

French police patrols were being supported by drones in scouring the mountain range on Saturday.

A senior police source said: ‘The enquiry is ongoing and being led by a public prosecutor with the assistance of judicial police and gendarmes.

‘There are still many questions to be answered, and that is why mountain searches are continuing.

‘Foot patrols are in the area, and they are using drones to try and find further evidence connected with the case.’

This would include Ms Dingley’s personal equipment, such as a yellow tent and red-and-grey rucksack.

The source confirmed that, while a tragic accident is being prioritised by those leading the enquiry, other theories, including foul play, have not been dismissed.

Her boyfriend Dan Colegate, who had been travelling with the Oxford graduate across Europe and living together in a camper van since 2014, said he ‘could no longer agree’ with the idea she had suffered an accident.

He told the BBC: ‘The search has been so prolonged and so intense, that as far as I’m concerned the probability of an accident is now less than the probability of a criminal act.’

Ms Dingley went missing in the area around Port de la Gléré, a mountain pass on the country’s Spanish border, while on a solo walk.

A huge search operation was at times hampered by poor weather conditions in complicated terrain and had to be called off in February, before resuming in late April.

Humans remains were first spotted on the Spanish side by a runner at around 2pm on July 23, before French authorities were alerted.

The remains were reportedly found at Puerto de la Glera, which is close to the 8,796ft Pico Salvaguardia summit where Ms Dingley last made contact with her partner around 4pm on November 22.

Specialist officers from Spain and France had carried out several searches of the area around the hiking trail.

The enquiry in France is now being led by Christophe Amunzateguy, the prosecutor of Saint-Gaudens.

He has been told by police colleagues that wild animals may have picked up the skull in a hidden gulley and transported it to the spot where it was found by Spanish hikers.

Brown bears and wolves are among the animals roaming freely in the Pyrenees, and birds of prey such as vultures are also a common sight.

‘This is the most plausible hypothesis,’ said Colonel Xavier Wargnier, one of the senior French officers involved in the search.

He confirmed that the skull was found at an altitude of 2,200 meters (7218ft) but that it could also have been dislodged by melting snow.

Mr Wargnier added: ‘It could have hurtled down the mountain during the Spring thaw.’

Mr Colegate and her mother Ria Dingley said in a joint statement that the discovery was ‘devastating beyond words.’

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