Police investigating the murder of Una Crown are putting up posters advertising the £10,000 reward for information.
The 86 year old's body was discovered in her home in Magazine Lane, Wisbech, at 10.45am on Sunday, January 13.
A post-mortem examination found she had died from stab wounds to her neck and chest. Her clothing was set on fire after her death in an apparent effort to hide her injuries and destroy evidence.
She was last seen on the morning of Friday, January 11, but had spoke to a friend by telephone at 5pm on the Saturday.
Now independent charity Crimestoppers have put up a £10,000 reward for information which leads to the arrest and conviction of those responsible for her murder.
Posters appealing for information are being put up around Wisbech and leaflets are being dropped through doors in the area of Magazine Lane.
Det Chief Insp Jon Hutchinson said: 'We hope the reward will motivate someone to come forward with that crucial piece of information we need.'
The £10,000 reward can only be claimed by those who provide information to Crimestoppers directly on 0800 555 111 which leads to the arrest and conviction of those responsible for Mrs Crown's murder.
Anyone involved in the murder will not be eligible to claim any of the reward.
Anyone with any information should call the Major Crime Unit on 101 or Crimestoppers, anonymously, on 0800 555111.
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