A burglar injured a pensioner as he fled the home of an elderly couple after stealing their gold and silver jewellery.
The elderly victim, in his 70s, was treated at hospital for a head wound following the confrontation, in Brentford, on March 8, and police said he is making a good recovery.
The thief took several items, including two solid gold bracelets, a solid silver ring and an unspecified sum of cash from the property, in Justin Close.
He confronted the man and his partner, who is in her 50s, as he fled their house at around 2.20pm, injuring the man in the process.
The burglar is described as black, around 6ft and aged in his mid-20s to mid-30s. He was slim, clean-shaven and was wearing a dark, zipped up fleece with the hood over his head.
Detective Sergeant Andy Thrower, of Hounslow Serious and Acquisitive Crime Unit, said: "Both victims are still understandably shaken and frightened as the circumstances of this attack could have resulted in a dire outcome.
"We are investigating the events which led to the suspect entering the victims' home.
"We are particularly keen to speak to anyone who may have witnessed suspicious behaviour in the vicinity of Brentford Docks between 1.45pm and 2.45pm that day."
Anyone with information is asked to call Hounslow Serious Acquisitive Crime Unit on 020 8247 6094, or Crimestoppers, anonymously, on 0800 555 111.