A fugitive lured police officers to him before shooting them repeatedly and then throwing a grenade at his victims, a court has heard.
Dale Cregan, 29, had evaded a nationwide manhunt when he set the trap, Preston Crown Court heard.
Mr Cregan denies killing PCs Nicola Hughes, 23, and Fiona Bone, 32, in Mottram, Greater Manchester last September.
He also denies the murders of David Short, 46, and his son, Mark, 23.
Mr Cregan appeared in court wearing a false left eye made of black onyx.
Mr Nicholas Clarke QC, prosecuting, said PCs Hughes and Bone were killed as they responded to a report of a burglary on the morning of 18 September.
Mr Clarke said: "[Cregan] lay in wait with a Glock firearm with an extended magazine that was fully loaded.
"PC Fiona Bone and PC Nicola Hughes attended. As soon as they arrived Cregan, who was on the run, shot the officers repeatedly, until his magazine was empty.
"As he left the scene he again threw a grenade towards the victims."
'Son died in his arms'
At the time the officers were killed, Mr Cregan was on the run and a suspect in the shooting of Mark Short and his father David Short.
The court heard the pair had been targeted after Mr Cregan was recruited with his friend, and fellow accused, Leon Atkinson - whose family had a long-running feud with the Short family.
Mr Clarke told the jury that Mark Short was shot at the Cotton Tree pub in Droylsden, Manchester, on May 25 last year
"At the time that his son Mark was shot, David Short, the head of the Short family, was using the toilet," said Mr Clarke.
"Otherwise he himself would have been a target. His son died in his arms."
On the morning of 10 August, David Short was at home in nearby Clayton when his killers came calling.
"He was chased through the house and shot many times," said Mr Clarke.
"He tried to run around the side of the house to escape. His injuries were already un-survivable and then a grenade was thrown on to him.
"Its explosion had devastating consequences for his torso.
"It is the first time in this country that a military grenade has been deployed in this way."
The catalyst for these attacks was a row on 13 May in the Gardeners Arms pub between Theresa Atkinson - dubbed "the matriarch of the Atkinson family" - and Raymond Young, a member of the Short family.
Mr Clarke said: "Theresa Atkinson was drunk and lashed out with a bottle, striking Young.
"It led to Raymond Young backhanding Theresa Atkinson."
She responded by shouting: "I'm going to get you done by my sons."
The jury was told Theresa Atkinson then phoned her son Leon, who contacted his two brothers and texted his "old friend" Dale Cregan.
Mr Cregan recruited Luke Livesey, Matthew James and Ryan Hadfield, the other defendants alleged to be involved with the Cotton Tree murder.
Mr Clarke said: "They [Mr Cregan and Mr Atkinson] decided to exact revenge for the lack of respect shown to Theresa Atkinson and so the shootings at the Cotton Tree were a direct reprisal."
Mr Cregan, Mr Atkinson, 35, from Ashton-under-Lyne, Mr Livesey, 27, from Hattersley, Damian Gorman, 38, from Glossop, Mr Hadfield, 28, from Droylsden, and Mr James, 33, from Clayton, are all accused of the murder of Mark Short and the attempted murders of three others in the pub at the time. All six defendants deny the charges.
Accused of the murder of David Short are Mr Cregan, Francis Dixon, 37, from Stalybridge, Anthony Wilkinson, 38, from Manchester, and Jermaine Ward, 24.
All four are also jointly accused of the attempted murder of Sharon Hark on the same day, and a single charge of causing an explosion.
They all deny the charges.
Mr Wilkinson is also charged with possession of a firearm with intent to endanger life and Mohammed Ali, 32, from Chadderton, is accused of assisting an offender. They deny the charges.
Only Mr Cregan is charged with the murder of the two police officers.
The trial continues.