Holocaust survivor Emmy Werner, 68, was murdered in her hotel room in Bayswater on 17 September 1972.
The widow was found dead in her bed by a chambermaid at Queens Hotel in Inverness Terrace at around 1pm.
She had been strangled and had suffered other serious injuries suggesting she had woken and disturbed her attacker.
The case remains unsolved: a 16 year-old boy was charged and put on trial at the Old Bailey but was acquitted in February 1973.
Before WWII Emmy, her husband Albert, a dentist, and their daughter Hedy lived a comfortable life in Brno, Czechoslovakia.
In April 1942 the family and other relatives were transported to Theresienstadt concentration camp near Prague. In October 1944 Albert was taken to Auschwitz and on to Kaufering concentration camp where he was killed in February 1945.
Emmy and her daughter, then aged 17, were liberated in May 1945 and came to London in September 1946 before settling in the Finchley area.
She moved to a residential care home in Finchley but regularly stayed at Queens Hotel while visiting her sister in central London.
On the evening before her death she went to the Vaudeville Theatre on the Strand with two friends to see Move Over Mrs Markham before returning to the hotel at 8.30pm.
Detectives believe she was attacked by a thief in her room in the early hours of the morning. Emmy was known to carry around cash in her handbag at it is thought someone came into the room to steal the money and attacked Emmy when she woke up.
Officers are hopeful people working at or visiting the hotel in the early ’70s may have useful information. At the time there were mostly young people of different nationalities both working and staying there, including some German tourists and Swedish staff.
In September 2017 the Metropolitan Police launched a fresh appeal for witnesses and offered a £20,000 reward for information leading to a prosecution.
Detective Inspector Susan Stansfield, of the Met’s Special Casework Investigation Team at the Homicide and Major Command, said: “Although many years have now passed since Emmy’s death it remains particularly difficult for her family that she survived the horrors of the Holocaust yet died in such brutal circumstances. Emmy was 68 years old and was physically and mentally vulnerable due to her past.
“The hotel served a mixture of guests and employed a number of staff who were spoken to by police at the time. However, with the passage of time, it is possible that the events of that night have since been discussed and there is information that could be really useful to our inquiry. Or maybe someone who was scared to speak to officers at the time might now feel able to come forward.
“Did you stay or work at the hotel or in the area of Inverness Terrace W2 in the early 1970s? Has anyone told you anything in confidence that you feel you should now disclose to police?
“We would also be interested in speaking to the friends – one from the hotel and an Italian woman – who Emmy went to the theatre with that night in case they have any useful information.
“We would ask anyone who can help to please contact us in confidence. Even if you think what you know is insignificant, we would ask that you come forward and let us assess what you tell us.”
Emmy’s granddaughter Carolyn Franks, 58, said: “My grandmother was a vulnerable woman and no one should have to die like she did, especially after the trauma she had already endured. The effect on her close family continues to be a source of great sadness to us and we feel whoever killed her should be held to account.”
You can provide information to police on 020 7230 4294 or the independent charity Crimestoppers anonymously on 0800 555 111.
This case is included on the Historical Murder Map of London.