Bone fragments have been found during a police search for the body of a Royal Navy sailor who is thought to have been murdered in Gibraltar in 1986.
Naval rating Simon Parkes, 18, from Kingswood near Bristol, disappeared while on shore leave with crewmates.
Police began searches of Gibraltar’s Trafalgar Cemetery on Monday after receiving new information.
Detectives said the bones “may or may not be human” and they were treating the discovery with caution.
They said their appeal for information had generated “promising leads” which would be followed up in the UK and Gibraltar.
Mr Parkes vanished when his ship, HMS Illustrious, docked in Gibraltar on 12 December 1986 on its return to Portsmouth from a deployment to Asia and Australasia.
He spent the evening in bars with crewmates but never rejoined the ship.
The case was reopened in 2001 after a shipmate, petty officer Allan Grimson, was convicted of two murders.
Grimson has denied involvement in Mr Parkes’ death.
In 2003, a number of Gibraltar cemeteries were searched after a police review concluded Mr Parkes was likely to have been murdered.
Police said the latest search, which had now been completed, was sparked by “credible” new information from a member of the ship’s crew.
Officers said they had found bone material which would undergo forensic tests.
Det Insp Roger Wood said: “While this is a positive discovery, we are cautious not to put too much significance on it at this time.
“On top of this, our activity has also generated new lines of inquiry from the public.”
The sailor’s parents, Margaret and David Parkes, said: “It is a very difficult time but we are optimistic that the search is not over and we will never give up hope of finding him.”