Police have launched an appeal for information in connection with the murders of a Playboy model and a teenager 40 years ago.
The DNA-linked murders of Eve Stratford and Lynne Weedon have never been solved despite extensive enquiries, the Met Office said.
Stratford, 22, who worked at London's Playboy club, was found with her throat slashed up to 12 times at her home in Lyndhurst Drive, Leyton, on 18 March 1975. She also had a nylon stocking tied round one ankle and a scarf round her hands.
Police said one witness recalled hearing a man and a woman having a conversation in her first-floor flat but it was not heated or confrontational. Then a short while later, another heard a loud thud noise coming from Stratford's first-floor flat. Her body was discovered by her boyfriend in the bedroom at 5.25pm. There was no sign of forced entry and no weapon was ever discovered. The cause of her death was knife wounds to the throat.
A recent DNA profile recovered from her body was later matched to Weedon, a 16-year-old schoolgirl, who was raped and murdered near her home in Hounslow on 3 September 1975. The cause of her death was a single blow to the head – her skull had been smashed with a heavy blunt instrument, which was also never found.
She had been on her way home when she was followed in Great Western Road into an alleyway called The Short Hedges where she was hit with a blunt instrument and thrown over a fence into the grounds of an electricity sub-station. She was then raped before the attacker left the scene.
Detectives have now launched a fresh appeal to mark the 40th anniversary of their deaths and are hoping the murder suspect, aged in his sixties and seventies, will come forward.
"The man who carried out these murders is now of a different, older generation. I would imagine he must have reflected upon his actions every day over the past 40 years," DCI Noel McHugh said. "Does he feel guilt, remorse, a need to explain what happened? Sadly Eve's parents have passed away but this man has a chance to bring peace to Lynne's mother and father, now in their eighties.
"I am directly appealing to that person to come forward and speak to us and make things right for the sake of the families affected."
Police believe the killer knew his victims, particularly Stratford, who had a huge circle of friends and acquaintances. It is also thought the murderer had a knowledge of Hounslow - the alleyway and sub-station are away from busy areas and would have meant Weedon's screams or struggles would most likely have gone unheard. It is not thought Stratford and Lynne knew each other.
Lynne's mother, Margaret Weedon, said: "It has been 40 years since our beautiful young daughter Lynne was violently taken from us. 1975 seems so long ago and it is. Forty years without her. We have missed out on so much; she missed out on life, no relationship or marriage, no career or children or even just travelling the world, all taken from her.
"We are left 40 years on always wondering what it would have been like. 1975 was a long time ago but events as traumatic as this stick in the mind so if you know or suspect anyone involved please help us."
Anyone with information is asked to call the incident room on 020 8785 8099 or Crimestoppers anonymously on 0800 555 111.