The court was told that on earlier in year, on May 25, Mark Short was shot in the Cotton Tree pub in east Manchester. He had been enjoying a night out with friends .
His father David was using the toilet otherwise he would have been a target, the court heard. Mark died in his father's arms.
Preston Crown Court has been told by prosecution that on September 18 2012 Dale Cregan called in a spurious burglary at Abbey Gardens in Hattersley, luring two unarmed police officers to investigate.
He lay in wait with a glock firearm, the court heard. Pc Fiona Bone and Pc Nicola Hughes attended. As soon as they arrived Cregan shot the officers repeatedly - until his magazine was empty. As he left the scene he threw a grenade towards his victims.
The prosecution is opening its case against Dale Cregan and nine others at Preston Crown Court. He denies murdering two police officers and two other men.
The family and loved ones of two police officers shot and killed in Manchester arrived at court amid high security.
Pc Nicola Hughes and Pc Fiona Bone were killed in a gun and grenade attack last year.
Dale Cregan is charged with their murder and his trial is due to start at Preston Crown Court today.
The trial of a man accused of the murder of two police officers in Greater Manchester will begin today.
Dale Cregan, 29, is accused of killing PCs Nicola Hughes, 23, and Fiona Bone, 32, in a gun and grenade attack, on September 18 last year.
He is also being tried for the murders of David Short, 46, and his son, Mark, 23, in the months before.
Nine other co-accused are variously charged with helping or taking part in one of the four murders and attempted murders, firearms offences or assisting an offender.