Hopes remain that the violent murder of a young woman half a century ago could still be solved.
Tuesday, March 10 marks the 50th anniversary of the murder of Susan Long, from Aylsham, who was sexually assaulted and strangled when she was just 18 years old.
Despite a major investigation into her death led by New Scotland Yard and later case reviews, the murderer has never been identified.
Cold case investigator Andy Guy said: 'Despite 50 years passing, Susan's murder is one of several cases we have that could be easily solved with single piece of information from the public.'
For more than 40 years her mother, Molly Long, lived with regular publicity about the murder, hoping her daughter's killer would be tracked down. She died without an answer.
Mr Guy, who is the major crime review and cold case manager in the police's Norfolk and Suffolk Major Investigation Team, said the case had been periodically reviewed since 1970.
He said: 'Operation China is the investigation into Susan's murder.
'Within that enquiry we have in our possession a full DNA profile of the person we believe murdered Susan. 'For many years we have worked to compare that sample with names put forward to us as and eliminated them from the enquiry.
'It only takes one call generated by strong suspicion for us to identify the offender, even if that person has since died.
'Susan's mother Molly, died six years ago never having had closure as to who killed her daughter, it is impossible to understand the pain she endured for all those years.'
MORE: Mum of murdered Aylsham teen leaves behind a legacy of hopeSusan was born and lived with both her parents in Aylsham, and worked as a clerk at Norwich Union in Norwich. She also had a boyfriend who lived in the city, and regularly travelled into Norwich by bus for work and to see him, as she had done on the evening of March 10, 1970.
Susan and her boyfriend went to the Gala Dance Hall on St Stephens Road, and she left at about 10.25pm to catch the bus back to Aylsham.
The bus arrived in Aylsham Market Place at 11.10pm.
It has always been assumed she got off the bus, but no one actually witnessed her getting off.
Susan's body was found at 5.15am on March 11 by a milkman on Burgh Road, about one-and-a-half miles from Aylsham's Market Place.
It is believed that Susan was driven to where her body was found but officers do not know if she went voluntarily or was abducted.
However, it is generally believed she would not accept a lift from strangers.
Following forensic recovery of semen left at the scene, it was established that the offender was from a rare blood group and blood samples were taken from men living in the Aylsham area.
Other forensic evidence included flakes of car paint found on Susan's clothing.
With the advance in DNA technology, and, more recently, familial DNA searching, hope has been renewed that the offender will be traced.
Since 2003, officers and staff have been researching DNA comparisons and DNA familial work.
However, 2010 has seen a new line of enquiry with DNA familial comparisons based on a likelihood ratio list which has resulted in new factors being built into familial searches.
Despite this extensive work, the offender has still not been identified.
Anyone with information concerning Susan's murder should call the Major Crime Review Team on 01953 423819.
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