An 86-year-old woman killed in her south-east London home was possibly attacked after confronting an intruder, the Metropolitan Police (Met) believes.
Jean Jobson's body was found with extensive head injuries in Oakridge Road, Bromley, on Sunday evening.
Officers believe she may have been attacked between 1800 GMT on Friday and 1000 GMT on Saturday.
A post-mortem examination has shown Mrs Jobson died of a blunt force trauma to the head.
Det Ch Insp Cliff Lyons said the injuries showed the victim had suffered a "substantial and concerted" attack.
The victim was attacked with a weapon, but the officer did not elaborate further.
'Creature of habit'
Officers forced their way into the property after concerned relatives of Mrs Jobson called the police.
The Met is trying to establish if anything was stolen from the property, but believes items have been moved about at the scene.
Mr Lyons said: "Jean Jobson was killed in her own home. She had suffered extensive head injuries.
"The post-mortem has confirmed she was the victim of a substantial and concerted effort by her attacker. This is a horrendous crime."
He added: "She was known locally as Pat. She was a creature of habit.
"She was mobile, used to do shopping for local market traders and frequented a cafe daily.
"The last time she was seen was Friday at around 6pm when a neighbour talked to her. I believe she was attacked between then and 10am on Saturday."
No arrests have yet been made in relation to the case.