Keith Cowell and his son Matthew died alongside Tony Dulieu
Killers who shot dead three men at a house in Hertfordshire used knives on a woman because they ran out of bullets, a police source has said.
Keith Cowell, 52, and his son Matthew, 17, died alongside 33-year-old Tony Dulieu, of Billericay, in the shooting in Bishop's Stortford on Tuesday night.
Police are working on the theory the attack was drugs related.
They are hunting two Asian men, aged in their early 20s, seen driving a red car away from the scene on Tuesday.
Mr Cowell's wife Nicole, 46, had left for work at Stansted Airport minutes before the gunmen arrived.
A woman, aged 54, believed to be Mr Cowell's sister, and a woman aged 23, believed to be Matthew's girlfriend Claire, were seriously injured. Their condition remains serious but stable.
A three-year-old girl called Angel, who is thought to be Claire's daughter, was found unharmed in the house in Plaw Hatch Close. She is now being cared for by child protection officers.
Mrs Cowell's brother Roger Spellane, 55, a kitchen fitter from Wood Green, London, said his sister had to formally identify her husband and son at the hospital morgue where their bodies were taken.
He said the older woman who was shot and injured in the incident had been Mr Cowell's sister. He said the younger woman was Matthew's girlfriend Claire.
Ch Supt Al Thomas, of Hertfordshire Police, said earlier: "We share the concern and sense of shock within the community.
"Early information suggests this was a targeted incident and not a random attack."