A gang of youths shot a man in the stomach after forcing their way into a family's house in west London.
The five men burst into the house in Balfour Road, Southall, at 1930 GMT on Saturday.
A man and woman in their 70s, a man in his twenties and a teenage girl were threatened and a family friend was shot in the stomach.
The gang then drove off empty handed.
The gunshot victim, who is in his 60s and visiting from Australia, is recovering in hospital following an operation.
Detectives are keeping an open mind about the gang's motive - but believe it was an attempted robbery which went wrong.
A Scotland Yard spokesman said: "The gang assaulted and abused the family, using physical violence and verbal abuse.
"They demanded items and, when they were refused, shot the male in his sixties in the stomach.
"All the suspects are described as black males wearing beanie hats, all in their teens or early twenties."