Investigators have confirmed that remains found outside an abandoned hotel in Bolton are human.
The skull was discovered by a couple who were filming around Egerton, just after midnight on Monday (March 1).
Forensic investigators are now working to establish the age of the skull and how long it has been there for.
Detectives are also working to ascertain how the remains came to be in the area.
According to Greater Manchester Police, they are not thought to be linked to any other investigations at this stage.
But officers say they are “keeping an open mind”.
A search of the undergrowth surrounding the derelict hotel where the skull was found is continuing.
Specialist officers are scouring the area for any further evidence.
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At this stage they have not yet uncovered anything further.
No arrests have been made.
Detective Inspector Debbie Hurst, of Greater Manchester Police's Bolton CID, said there is no wider threat to the public.
“This was a very surprising discovery made in the early hours of Monday morning and we have been working ever since to establish the circumstances here,” she said.
“What we do know is that the item found has been confirmed to be a human skull, but it is still unknown how old the skull is and how long it has been at the location for.
"These enquiries by specialist forensic officers are ongoing and will be determined in due course.
“By the very nature of this discovery, we do understand some concern in the community and of course the sheer intrigue that this investigation brings with it, however we are confident that there is no threat to the public and that this isn’t currently linked to any other ongoing investigations.
“We are keen to establish the facts as soon as we can but the work that is ongoing must be conducted thoroughly and properly before we get to that stage.
“If anyone has any information about this discovery that could aid our enquiries we ask that they make contact with police.”
Police were called to a report of a suspicious item being found off Blackburn Road, Egerton, at around 12.35am yesterday.
Officers attended and found what they described as “possible human remains” in the undergrowth outside the hotel.
GMP say these remains have since been confirmed by forensic officers as a human skull.
A cordon remains in place in the wooded area close to the former hotel.
Danny and Felicity Duffy have spoken of their shock after discovering the skull.
They also found an army style jacket close to the remains.
The couple immediately dialled 999 to alert police after stumbling upon the remains just after 12.30am
Danny said they were “shaken up” by the discovery and were unable to sleep after police released them from the scene at around 3.30am.
“I’ve not slept,” Danny said. “I can’t get it out of my mind. I’ve never come across anything like that before.
“We both felt sad. Felicity has been quite upset.
“We’ve only slept for about an hour. As soon as I woke up I thought it was a bad dream.”
The couple - who run a paranormal investigation YouTube channel - were in the area filming when they made the sad discovery.
“We were doing our normal routine and about 10 or 15 minutes in we spotted something,” Danny says.
“There was a jacket on the floor. Then I saw what looked like a pebble on the floor.
“I moved the bushes to the side and it was a human skull in the tree line. It really did give us a shock.
“My legs turned to jelly. We rang the police straight away.”
He added: “A police van came down almost immediately and two officers came to the scene.
“We were sat in the back of the police van for almost four hours.”