Dale Cregan fired a full magazine of bullets at two women police officers after luring them to a house with a "spurious burglary" report, a court has heard.
The 29-year-old is accused of killing PCs Nicola Hughes, 23, and Fiona Bone, 32, in a gun and grenade attack last year.
In an opening statement, prosecutor Nicholas Clarke QC said he went on the run after gunning down former amateur boxer Mark Short at the Cotton Tree pub in Droylsden, Greater Manchester, in May, and later the man's 46-year-old father David.
Then on September 18, the court heard, Cregan called in a "spurious burglary" at an address in Hattersley, luring the two unarmed officers to investigate.
The prosecution said he lay in wait with a Glock firearm with an extended magazine that was fully loaded, which he fired repeatedly at the officers when they arrived.
It is then claimed he tossed a grenade towards the officers. Both died from their injuries.
Cregan denies four charges of murder, four of attempted murder and one of causing an explosion.
Jurors also heard about the attack on Mark Short and were told it was "revenge" for lack of respect shown to the mother of a rival family called the Atkinsons.
The trial takes place amid one of the tightest security operations ever mounted for a court case, with more than 150 police officers surrounding Preston Crown Court.
Armed officers are positioned on overlooking rooftops and sniffer dogs have been used to check surrounding shrubbery and walls.
Cregan arrived in a convoy of vehicles earlier this morning, as a helicopter hovered overhead.
He appears alongside nine alleged associates.
They all deny a range of offences including murder, attempted murder, causing an explosion, possessing a firearm and assisting an offender.
The jury for the 12-week trial was sworn in earlier this week and the lawyers have spent three days locked in legal argument about the details of the case.
The trial continues.