The Bloody Sunday inquiry is to reconvene a month after it came to a formal end so it can hear the evidence of one more witness.
A formal announcement from inquiry chairman Lord Saville is expected to be made today.
Notification was sent yesterday to legal teams representing the families of those who died, together with the representatives of soldiers.
The inquiry into the shooting dead by paratroopers of 13 civilians on a civil rights march in Derry on January 30th, 1972, closed at the end of last month.
During four-and-a-half years in session it heard from 921 witnesses and received 1,555 written statement.
Lord Saville and his two co-panellists then went away to compile their report, which is not expected to be handed to the Government before next summer.
However, they now want to hear from a Witness X who, according to RUC notes dating back to 1972, told them he was a member of the Provisional IRA on Bloody Sunday and that in a joint operation with the Official IRA opened fire from the Bogside.
The shooting was said to have been in an area where many people were killed and where soldiers have told the inquiry they saw men with guns.
The IRA has always denied opening fire on Bloody Sunday and claimed its weapons had been moved out of the Bogside for the day.
Witness X made a statement to the Bloody Sunday lawyers two years ago denying firing and even being in the PIRA.
The witness was issued with a subpoena last January ordering him to give evidence to Lord Saville but he did not attend, citing medical grounds.
Now Lord Saville is understood to have decided he needs to hear from him and is planning a sitting in the New Year.
PA