Detectives have renewed a fresh appeal for information on the 40th anniversary of the murders of a Playboy bunny and a teenager.
Eve Stratford, a 22-year-old who worked at London's Playboy club, was found with her throat slashed in her Leyton home on the evening of March 18 1975.
Six months later, 16-year-old schoolgirl Lynne Weedon was brutally attacked and raped in an alleyway near her home in Hounslow at 11pm on September 3, as she returned from a night out with friends.
She was found abandoned and barely alive at an electricity sub-station the next morning and died a week later.
Both murders were linked in 2004 after matching DNA was discovered on the victims, who were not thought to have known each other.
Lynne's mother Margaret Weedon has made an impassioned plea for information as the anniversary of her daughter's death approaches.
She 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 - a true life sentence."
The teenager is believed to have been followed home from the Great Western Road (the A4) into an alleyway called The Short Hedges, where she was hit with a blunt instrument and thrown over the sub-station fence.
Her attacker then raped her before leaving the scene.
Mrs Weedon added: "We are well aware that whoever murdered Lynne also murderedEve Stratford. That young lady also had her life snubbed out. Her family have died now. Another true life sentence."
Eve was last seen walking alone near her home home in Lyndhurst Drive, Leyton, shortly before 4pm on a snowy day in March.
She was found dead with her hands tied by a scarf in the bedroom of her flat at 5.30pm, after her neck had been savagely cut almost a dozen times.
An hour earlier a neighbour had heard a male and female voice talking, apparently calmly, in Eve's flat. There was no sign of forced entry.
Investigating officer Detective Chief Inspector Noel McHugh said the suspect for both murders is likely to be in his 60s or 70s.
He added: "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.
"It's inconceivable the killer of Eve and Lynne has kept the perfect secret for 40 years. It's a heavy burden to carry and he must have let details slip over the years - maybe to a partner, a friend, even a cellmate - and I would appeal to anyone with information to contact us."
Police believe the killer would have known of the Hounslow area - the alleyway and sub-station where Lynne was found were away from busy areas and meant her screams would have not been heard.
Mrs Weedon said: "I will make a mother's plea for anyone who can tell us some information about the person who took my daughter and Eve Stratford's lives to come forward. Please, please give us some sort of closure."
Anyone with information is asked to call the incident room on 020 8785 8099 or Crimestoppers anonymously on 0800 555 111.