Twenty-five years ago today, loyalist gunmen sledge-hammered their way into the Belfast home of lawyer Patrick Finucane and shot him dead in front of his wife and young children.
Since then, compelling evidence has emerged to show that UK state agents were involved in the killing. Those who directed and took part in the attack were mainly agents and informers of the British Army's Force Research Unit (FRU). The police and intelligence services were aware of previous plans to kill Finucane but did not warn him because they preferred to protect their agents inside the paramilitaries. One of the two murder weapons, a Browning pistol, was recovered by police but then given back to the British Army, from whom it had previously been stolen by a soldier and sold to loyalists.
By anyone's definition, this was a murder with collusion written all over it.
Yet, twenty-five years on, the UK government still refuses to establish an independent public inquiry into his death. The Finucane family and the public are denied the full truth.
This weekend's vigil in Belfast for Patrick Finucane was a protest in darkness, a sadly apt reminder of the failure to hold the darkest details of his murder to the light.
Looking at successive governments' responses to calls for an independent public inquiry proves instructive. Margaret Thatcher's government point blank refused to hold one. Tony Blair's offered to hold one and then reneged.
In April 2004 retired Canadian Judge Peter Cory-appointed by the British and Irish governments to investigate the key cases of alleged collusion by the RUC, British Army and the Gardaí- recommended public inquiries be established into the Finucane case and three others in Northern Ireland and a double-murder in the Republic. All except Finucane have now had their inquiry.
The coalition government has thus far sought to avoid an inquiry by appointing an eminent lawyer, Sir Desmond De Silva QC, to privately review the paperwork held by the State. His report found there had indeed been State collusion in Finucane's killing but failed to hold accountable anyone who had authorised the murder.
Finucane's widow, Geraldine, branded the review a "whitewash". She holds out some hope that a future Labour government might, finally, set up the inquiry that all the previous ones have failed to deliver. Patrick's son, John, also a lawyer now, told Amnesty: "We continue to feel the deep personal loss even after 25 years, yet we remain convinced the best way to honour what my father stood for in life, and in death, is to continue our campaign for truth and justice."
The actions of Conservative, Labour and Coalition administrations since 1989 to obfuscate, prevaricate and evade only increases suspicions of the worst possible motives - that agents of the State, with the knowledge and possible tacit approval of senior figures in the government of the time, conspired with a paramilitary organisation, to kill a high-profile lawyer.
If, indeed, that is the truth it should cause every person who believes in the rule of law to shudder. If it isn't then that assurance can only be delivered through a full, public inquiry. The continued refusal to air the facts and investigate allegations about security personnel is not only cruel, but positively sinister.
And this feeds into a wider narrative of failure. The Finucane case is also a stark reminder of the broader failure to address Northern Ireland's three decades of bloodshed.
Even though no one has been held accountable for vast majority of the 3,500-plus killings carried out during the Troubles, there are those who would rather draw a veil over it all. Northern Ireland's Attorney General recently suggested there should be no more investigations or inquests into any such cases. While the UK government was quick to rebuff the Attorney General's proposal, Ministers have not been so convincing in signalling a willingness to play their part in investigating outstanding human rights violations and abuses.
Bereaved family members of those killed in the 1998 Omagh bomb have also been denied an inquiry by the current Northern Ireland Secretary Theresa Villiers. Serious questions have emerged about State failures in the lead up to, and the aftermath of, the single biggest atrocity of the Northern Ireland Troubles, yet the government still sees no need for a public inquiry into what happened.
The government's failure to establish inquiries into these killings is symptomatic of a wider failure to effectively address the past in Northern Ireland and ensure accountability for the human rights violations and abuses committed by all sides during three decades of violence.
If the people of Northern Ireland are to be allowed to move on from their bloody recent past, then all parties to the conflict - including the UK government - must be willing to come clean. Only then will the Finucanes and thousands of families like them be able to lift the shadow of the past from their future.