The death of a frail pensioner whose body was discovered in his home is being treated as murder.
Robert Simpson, 67, was found dead at the property in Mayfield Drive in Armadale, West Lothian, at about 9pm on Saturday.
He had been assaulted and suffered serious head injuries, said police.
Mr Simpson, also known as Ronnie, was described as a small, frail man who often walked with a stick or crutch and would have been "unable to defend himself".
The last confirmed sighting of him was at his home on Wednesday October 3, although police said they were following up unconfirmed sightings of him since then.
Lothian and Borders Police also said there were reports of a disturbance at his home on Friday at about 10pm. However, the force said when officers attended and conducted inquiries there were "no signs of anything untoward".
Detective Superintendent Bob Cowper said: "While the exact circumstances surrounding Mr Simpson's death are still unclear, his injuries are consistent with a particularly brutal assault. Mr Simpson suffered from a number of health problems and he was a frail man who would have been unable to defend himself.
"I would appeal to anyone with information on Mr Simpson's whereabouts from last Wednesday to come forward to help us find the person or people responsible for his death.
"I would also appeal to anyone in the local community with any information, no matter how insignificant it might seem, to come forward immediately."
Police are also appealing for any information on visitors to and from Mr Simpson's home since October 3.