On Thursday, 22 June, 1995, Christine McGovern was found strangled in her flat in Walthamstow, east London.
The 47 year-old lived alone with her Rottweiler dog at a flat at 53a Hamilton Road and was a known sex worker.
She was last seen alive at around 6.30pm on June 21, 1995, in the street outside and at 11pm neighbours heard a dog barking.
At 12pm the next day a friend found her lying naked in her flat. She had suffered a broken spine and nose and severe bruising and a pathologist gave the cause of death as asphyxiation.
There was no sign of forced entry to her home but it had been ransacked and a video recorder, a satellite decoder, four gold rings and a gold necklace with a St Christopher’s pendant had been stolen.
Detectives believe she was murdered by someone she knew and issued a new appeal for witnesses and information in 2011.
Detective Inspector Ken Hughes, of the Homicide and Serious Crime Command, said: “We are appealing for anyone who didn’t originally come forward to contact us.
“Circumstances change over the years and it may be someone now feels they can approach us in confidence and anonymously if they wish.
“Even if you just have a hunch or had suspicions about someone at the time we would like to hear from you – we can quickly eliminate people from the enquiry from the evidence we have recovered from the scene but a piece of information you may think is useless could be crucial.”
Contact Crimestoppers anonymously on 0800 555 111.