By UTV reporter Jordan Moates
A former soldier thought the border checkpoint was under attack on the day Aidan McAnespie was shot dead, Belfast Crown Court has heard.
He was giving evidence in the trial of David Holden, who is accused of the 23-year-old's manslaughter.
Holden denies the charge against him.
Belfast Crown Court was told how Mr McAnespie parked his car close to the checkpoint in Aughnacloy in February 1988.
A soldier who was on duty watched him pass through on foot and shouted to the accused in the Army sanger that Mr McAnespie was approaching.
The court heard he did that because the Mr McAnespie was regarded as a person of interest.
The guardsman said he heard a burst of automatic fire a short time later after Mr McAnespie had gone out of his sight.
The witness believed the border checkpoint was under attack, he said he cocked his weapon before setting off the alarm.
When pushed about what else he heard, the former soldier said he heard a shrill from Holden which he described as a high pitched sound.
He then moved to where the accused was positioned, telling the court he saw Holden with his hand on the butt of the machine gun looking very shocked.
Later, the guardsman told the judge his immediate thought was there had been a negligent discharge.
Mr McAnespie died after one of the shots fired from the machine richoched off the ground striking him in the back
The court was also told the day of the shooting was Holden's first carrying out that particular sentry duty.
The case continues.