CCTV images have been released of an 86-year-old woman four days before she was found battered to death in her south-east London home.
Jean Jobson - known as Pat - was found with head injuries at her home in Oakridge Road, Bromley, on 20 February.
Police said Mrs Jobson lived alone after losing her husband eleven years before and did not have any children.
The CCTV images show Mrs Jobson wearing similar clothes to what she was wearing on the day she died, police added.
Det Ch Insp Cliff Lyons said the public had reacted strongly to her death.
"We believe that Pat fought her attacker and I cannot appeal strongly enough to the local community to come forward," he added.
Mrs Jobson is believed to have worked as a bus conductor, a secretary for London County Council and was a member of the Territorial Army for a time.
She was last seen at about 1700 GMT on 18 February. Police believe the assault took place between this time and 2000 GMT on 20 February.
She was found suffering from head injuries and was pronounced dead at the scene. Post-mortem tests showed she died from a blunt force trauma to the head.
No arrests have been made.
Anyone with information has been asked to contact the Metropolitan Police or Crimestoppers.