A pensioner suffering from dementia was left with black eyes as well as head and nose injuries after a burglary in Herne Hill.
CCTV images of a man police suspect was behind the break-in, which took place on Monday, May 12, have been released.
Officers were called shortly after 11am by a 58-year-old woman who said she left her home in Fawnbrake Avenue at 7.30am and returned to find her husband with a head injury.
The 70-year-old victim suffers from short term memory loss and struggles to communicate.
Drawers throughout the house had been searched and two laptops as well as a mobile phone were stolen.
CCTV footage obtained by officers showed a suspect had been at the house shortly after 9am, opening the gate and walking up to the front door.
The footage then shows the man loitering around the door for a short while before he goes out of view having approached one of the two front sash windows.
The man is then seen again leaving at 9.20am through the front door and walking off with a blue and black rucksack.
DC Anne Hogarth, Serious Acquisitive Crime Unit Lambeth: "We are keen to trace the man pictured in the CCTV, we still do not have a full picture of what took place as the victim suffers from dementia.
“When the victim was found he was very badly injured (with injuries to his head, nose and bruising to both eyes). He also suffers from short term memory loss and struggles to communicate.
"This incident has been very upsetting for the victim who is being supported by his family.
“I urge anyone who knows the man pictured in the CCTV or was in the area at the time to search their conscience and come forward.
“I am sure that they would feel disgusted if had happened to somebody from their own family."
Call 020 8649 2153 or 0800 555 111 anonymously with information.