Keith Cowell, his son Matthew and a third man were shot dead
A drug dealer pointed in court to two men he said murdered members of his family and a friend in Hertfordshire.
Ian Jennings pointed out Kevan Thakrar, 21, of Stevenage, and Miran Thakrar, 24, of no fixed address, who both deny murder at St Albans Crown Court.
Keith Cowell, 52, his son Matthew, 17, and Tony Dulieu, 33, from Essex, were shot dead at the Cowells' Bishop's Stortford house on 28 August 2007.
Mr Jennings, 32, identified Miran Thakrar as the man with the gun.
Mr Jennings told the court earlier that he was at the house to complete a drugs deal.
Under questioning by Brendan Kelly QC, for Miran Thakrar, he denied the killings were carried out by a black man and a mixed race man.
Mr Jennings said: "The two men are sitting at the back. Those two there done all the shooting. The one on the right had the gun."
He told the court: "I was there while the murders were going on. I supplied the drugs that caused the murder."
The prosecution claim Miran Thakrar was angry after having been supplied with low grade cocaine in a previous deal.
Mr Jennings' mother Christine, 54, was shot in the foot and stabbed and Matthew Cowell's girlfriend Claire Evans, 23, was stabbed as she protected her four-year-old daughter during the incident, the court heard.
Kevan and Miran Thakrar deny attempting to murder the two women.
The Thakrars also deny possession of an Ingram Mac 10 sub-machine gun with intent.
The defendants' brother Jay Thakrar, 25, of Lomond Way, Stevenage, denies two counts of assisting an offender.
Their father, Atul Thakrar, 47, of Compton Place, Northwood, London, pleaded not guilty to assisting Kevan Thakrar to attempt to leave the UK between 28 August and 5 September.
Co-defendant Amanda Dansie, 21, of High Street, Buntingford, Hertfordshire, pleaded not guilty to assisting in the escape of Miran Thakrar from the UK between 28 August and 9 September.
Yilay Tufensoy, 20, of Nags Head Road, Enfield, London, denies two charges of assisting an offender.
The trial continues.