It's a short letter, five brief paragraphs dated April 27, 2009, almost six years ago.
But throughout a week of thrashing about in the stormy waters of sex abuse allegations, the Sinn Féin party have clung to this missive like a drowning man cleaving to a rock.
It was written by then-Sinn Féin TD for Louth Arthur Morgan, to Paudie McGahon, who was raped by a senior IRA figure in the early 1990s.
"I would like to confirm my strong advice to you to make a formal complaint to the gardaí about these allegations," it stated.
"They are the competent authority to investigate these matters and, if a case can be constructed, to bring it before the courts."
Since last week's revelations by Paudie McGahon on BBC NI's 'Spotlight' programme, this letter has been used time and again by Sinn Féin to deflect awkward questions about who knew what, and when, regarding the allegations.
On Wednesday, the day after 'Spotlight', Sinn Féin leader Gerry Adams read out the Morgan letter on 'Morning Ireland', and again gave details of it on RTE's 'Six-One News' that evening. It was raised by Donegal's Padraig MacLochlainn later the same evening on 'Prime Time'.
Mary Lou McDonald brought up Arthur Morgan's role on Newstalk on Thursday.
As did Pearse Doherty on Radio One's 'Saturday View', arguing the letter was proof that there has been no cover-up by Sinn Féin. "If we were trying to cover up abuse, then why would one of our TDs be suggesting that the victim go to the gardaí and inform on the alleged abuser and the circumstances surrounding the abuse?" he asked.
On Sunday, Padraig MacLochlainn again discussed the letter on 'The Week in Politics'.
It was, he insisted, "documentary evidence" that Sinn Féin had urged the abuse victims to go to the authorities.
In truth, the much-invoked Morgan missive is a distraction from other key questions relating to Sinn Féin's response, particularly given Mr McGahon's assertion that he told a Sinn Féin councillor in 2002 about the abuse and the subsequent kangaroo court.
But one thing is certain - when the going gets tough, Spin Féin gets going.
Time and again throughout the past week, the same phrases popped up repeatedly in both a succession of interviews with Sinn Féin TDs, and also in the Dáil chamber.
The pattern contained several key elements which used almost identical language:
Strongly-worded pleas for anyone with information on any abuse to bring the information to the gardaí or the PSNI, as no victim should "be afraid". Or bring the information to a Sinn Féin person, and the party will offer "every possible support".
Strong condemnation of the alleged IRA perpetrators who must be brought to justice and who have "brought shame" on Republicans.
Strong condemnation of "scurrilous attacks" by the party's "political opponents" who have used the issue for "political point-scoring". Insistence that Gerry Adams knew nothing until 2009, except that an allegation was made and that Arthur Morgan had dealt with it "in an appropriate fashion".
Criticism of the Taoiseach for his delayed response of several months to the proposal by Martin McGuinness for a North-South initiative.
The uniformity of the responses is quite remarkable as the wagons continue to circle around the boss. Not one member of the party has expressed any doubt in Mr Adams's assertions that he heard, saw and spoke no evil. When asked on Sunday by 'TWIP' presenter Áine Lawlor if he thought his leader should resign, Padraig MacLochlainn's immediate and emphatic reply was "absolutely not".
It can't be easy (and their outrage is evident) for those baggage-free TDs who have been dispatched to deal with what the party insists is a legacy issue - just like flags, parades and emblems - from a time when mistrust of the police was rife in the North.
But the fact is that the events involving Paudie McGahon and Mairia Cahill aren't mired in the North's dark history. They happened post-Peace Agreement, and in Paudie's case, in the Republic.
But that's an inconvenient truth for the harmonious Spin Féin chorus.
The prominent SF figure at the centre of the latest child abuse allegations continues to be involved with party activities.
Despite the furore over the sex abuse claims engulfing the party, it was business as usual for the Dublin-based figure.
The man was accused of abusing a teenage girl, who was also later subjected to an IRA kangaroo court. Despite the allegations against him, the figure continued to be involved in party activism yesterday.
According to a secret document about an internal Sinn Féin "inquiry" into IRA abusers, alleged to have taken place in 2006, the prominent figure is accused of sexually abusing a 13-year-old girl, who was known to him. The girl spoke to child services, but was also interviewed by "republican movement" figures.