Detectives are re-appealing for information on the third anniversary of the murder of Wisbech widow Una Crown.
The burnt body of the 86-year-old was discovered in the hallway of her bungalow in Magazine Lane on Sunday, January 13, 2013 by her nephew-in-law.
She was last seen alive on Friday, January 11, but had spoken to a friend on the phone at about 5pm on the Saturday.
A post-mortem examination revealed she died as a result of stab wounds to her neck and chest. Her body was then set on fire in an apparent attempt to disguise her injuries and destroy evidence.
Detective Chief Inspector Jerome Kent, from the Bedfordshire, Cambridgeshire and Hertfordshire Major Crime Unit, said: 'Three years on from this tragic incident, Mrs Crown's killer remains undetected, and I'm urging anyone who has information they have kept quiet until now to contact us.
'We still believe the answer to solving this case lies within the local community, so I ask people to really think back to what they were doing this time three years ago - did you see anything suspicious? Did someone you know come home smelling of smoke, acting strangely, or had clothing that was burnt or had blood on it?
'Someone out there knows what happened to Mrs Crown and I am pleading with them to do the right thing and contact police.
'Any information, no matter how small or insignificant it may seem, may hold the key to solving this tragic case. We are determined to get justice for Mrs Crown and her family.'
Police have previously been criticised over their initial handling of the case.
When news of Mrs Crown's death was initially made public police ruled it was not suspicious, two days later they admitted she had been brutally murdered in her bungalow sometime between 5pm on Saturday January 12 2013 and Sunday morning when her body was discovered by a relative.
Coroner William Morris told an inquest into Mrs Crown's death last March that police 'too readily dismissed' foul play or circumstances.'
The inquest heard the first officers on the scene of the murder thought Mrs Crown may have died by a tea towel catching fire on an old cooker which made her panic and caused a heart attack.
But it wasn't only the police who overlooked the possibility of it being a murder – fire chiefs and paramedics also failed to spot the signs, the inquest was told.
A report by the professional standards department of Cambridgeshire police said the actions of both officers had 'breached the standards of professional behaviour'.
But it wasn't only the police who overlooked the possibility of it being a murder – fire chiefs and paramedics also failed to spot the signs, the inquest was told.
Since then police have upped their game and a reconstruction of the case was broadcast as part of the BBC's Crimewatch programme in April 2013, which lead to a number of 'interesting calls.'
It also revealed that Mrs Crown's gold wedding ring together with some cash was missing. The ring and the murder weapon have never been found.
Anyone with information should call the Major Crime Unit on 101 or Crimestoppers, anonymously, on 0800 555 111 or via their online reporting system at www.crimestoppers-uk.org.
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