The jury at the Dale Cregan trial at Preston Crown Court has been told he lured two police officers to him before shooting them repeatedly and then throwing a grenade at his victims.
The 29-year-old denies murdering former Isle of Man resident Fiona Bone and her Greater Manchester police colleague Nicola Hughes in Tameside last September.
Dale Cregan is standing trial with nine other co-accused - whose charges include murder and attempted murder, in relation to other killings.
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, "He 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."
The trial continues.