A Former RUC Special Branch officer told the inquiry yesterday that Gen Robert Ford appeared to be in command behind the main army barrier before paratroopers began their move forward into the Bogside.
Elaborate security precautions were in place for the hearing of evidence from Mr William George Hunter, who served for over 40 years with the RUC and was in the Special Branch for over 30 years.
He gave evidence from behind high wooden screens so that he was visible only to tribunal members, lawyers and technicians. As he left the Guildhall by a side door, an armoured Land Rover and armed police formed a protective wall.
Mr Hunter was shielded from photographers and onlookers by wooden panels carried by tribunal staff as he got into a vehicle with darkened windows and was driven away under armed escort.
In his evidence, he maintained that on Bloody Sunday he had heard the sound of nail bombs exploding in the Rossville Street area, followed by "the beat of a Thompson sub-machine gun", before he heard "sharp automatic fire" from what could have been military weapons.
Mr Hunter said he had travelled from Belfast with two Special Branch colleagues and was briefed in Derry's Victoria Barracks before being detailed for duty in the Waterloo Place/William Street area.
Their brief was to identify "known troublemakers, prominent Republican activists or terrorists" who might have infiltrated the proposed Civil Rights march to the Guildhall.
Replying to Mr Alan Roxburgh, counsel to the tribunal, he said that, in the event, he did not see anyone who fell into those categories. He therefore made no notes.
The witness said his recollection was that Gen Ford, Commander of Land Forces, Northern Ireland, was present near him behind the army barrier for most of the time he was there.
"He appeared to be in charge of the situation," he said. In reply to Mr Arthur Harvey QC, for a number of victims' families, Mr Hunter agreed that when he was debriefed that evening, he was aware that something had gone terribly wrong.
He repeated that he believed he had heard nail bombs and a Thompson gun as the army went into Rossville Street.
He might have been "slightly out of sequence", but he was not misleading the tribunal.
Mr Harvey suggested to the witness that he was wrong, and that "even the army do not claim the sequence that you do", but the witness said that while he might be out of sequence, he believed he was correct in what he said he saw and heard.
Questioned by Ms Eilis McDermott QC, for the family of Patrick Doherty, the witness agreed that the description of these events in his report to a superior officer was "very similar" to that in a report by his colleague, Det Constable McGarvey.
He said: "I do not believe that I would have colluded with him to prepare similar reports."
Replying to Mr Michael Mansfield QC, for relatives, he agreed that when he wrote his report a few days after Bloody Sunday, he knew that the one thing that was significant and important was whether the soldiers were justified in what they did.