Police hunting the killer of a teenage servicewoman more than 50 years ago have urged the public "just give us the name" of who they suspect murdered her.
Rita Ellis, 19, was sexually assaulted and strangled at RAF Halton, Buckinghamshire, in November 1967. Her body was discovered in nearby woodland.
A new DNA profile had enabled police to eliminate almost 200 suspects in 2017.
Thames Valley Police's Peter Beirne said there would be "people out there who have suspicions" over the killer.
He added: "Just give us the name of who you suspect, we don't need any of your personal details."
A number of arrests were made during the initial investigation but no charges have ever been brought.
Police reopened the inquiry 10 years ago to make use of modern forensic techniques.
Miss Ellis's body was discovered in Rowborough Copse near a disused railway near the RAF camp on 12 November by a dog walker. She was last seen alive the previous night.
Efforts had been made to hide the remains of Miss Ellis, from Stevenage in Hertfordshire, under leaves and foliage.
Mr Beirne, head of Thames Valley Police's major crime review team, said the killer "will have had this horrific act on their conscience for 53 years".
"There has to be a possibility that they have confided in someone during this time.
"If you have any information, even if you think the information is insignificant, please come forward."
During an appeal three years ago, Miss Ellis's sister Tina Streeter, who was 10-years-old at the time of the murder, said: "It's just through a freak incident - an opportunist - some evil, sick person who just couldn't contain themselves, I don't know their motive."