The former Northern Ireland ombudsman, Mr Stephen McGonagle, has said in a statement to the inquiry that on Bloody Sunday he saw a young man with a handgun being quickly disarmed "by two people who I knew to be IRA activists".
Mr McGonagle also reveals that, while he was not involved in the organisation of the civil rights march on the day, the organisers had asked for his opinion and advice.
Mr McGonagle's statement is among those submitted by a number of witnesses who, the tribunal has decided, are not to be called to give oral evidence. At the time of Bloody Sunday, and before his later appointment as Ombudsman, he was a retired trade union official.
He said in his statement that at that time there was widespread unhappiness about what was happening in the North "and the general consensus was that the best way to demonstrate the people's wishes to the British government was to hold a number of peaceful marches".
He also said the organisers were emphatic that the march should be peaceful, that there should be no rioting or shooting, and that anyone causing trouble would be dealt with.