The killing of a Northern Irish soldier and two other UK troops was a well-planned operation carried out by an Afghan soldier who had been forced into committing the atrocity, an inquest has heard.
An officer who survived the attack that killed Co Armagh soldier Lieutenant Neal Turkington, Major James Joshua Bowman and Corporal Arjun Purja Pun, said he believed Sergeant Talib Hussein had been threatened with retribution if he did not carry out the massacre.
The soldiers, who all served with the 1st Battalion The Royal Gurkha Rifles, were gunned down by Hussein at their base in Helmand on July 13 last year.
Captain Peter Houlton-Hart, who was a liaison with the Afghan Army, said he did not believe Hussein was a Taliban infiltrator.
"It could have been something as simple as someone's found his family and they've said 'we'll kill your family unless you kill some ISAF'," the officer told the inquest.
Capt Houlton-Hart described how he was awoken shortly after 2am on July 13 by gunfire.
"I rolled out of bed and grabbed the body armour and helmet and my rifle. When the second round of incoming fire came in it became clear there was someone inside shooting."
He said he had little time to react before there was an explosion in the direction of a tent where the fire support team were.
"I didn't hear a whoosh but what I saw afterwards was a hole from where RPG went through the side of Maj Bowman's tent and out to the area where the fire support tent used to be," Capt Houlton-Hart said.
Post mortem examinations found that Lieutenant Turkington, Major Bowman and Corporal Pun all died from gunshot wounds, the inquest was told.
The inquest was adjourned until today.
Hussein (23) shot dead Lt Turkington (26) from Portadown and Cpl Pun (33) from Nepal, who were working in the command centre of Patrol Base 3 in Nahr-e Saraj district, near Helmand's capital Lashkar Gah. The intelligence officer also shot dead shot Maj Bowman (34) from Salisbury, Wiltshire.