A couple from Horsham who were threatened with a shotgun and a machete by raiders were deliberately targeted, police have said.
Up to six men men burst into the house in Longfield Road at 1915 GMT on Wednesday, struck the man in the face and threatened both victims.
Det Insp Pierre Serra, from Sussex Police, said: "This house was not selected randomly
"It appears to have been specifically targeted by the offenders."
Both victims, who are in their late 50s, were taken to the East Surrey Hospital for treatment.
Det Insp Serra said the attack had left the couple traumatised.
Sussex Police have refused to discuss possible motives for the attack.