Donaldson, 56, appeared at a Sinn Fein press conference in December to confess that he had been working for British intelligence for more than 20 years, betraying dozens of his colleagues and friends.
Immediately afterwards, he quit Belfast, adopting a low profile and renting a small, isolated cottage in County Donegal. Tracked down by a newspaper two weeks ago, it became clear that despite his long years of service to MI5, he was receiving neither protection nor monetary compensation from the British. Having served his purpose, he died violently and alone.
In 2002, Donaldson was at the center of a huge political storm. He was charged with operating a spy-ring for the IRA within the North’s power-sharing government and parliament at Stormont.
The high-profile police assault on his office and home, dubbed “Stormontgate” provided the British government with an excuse to suspend the power-sharing government, placing the blame firmly on republicans.
For this reason, Donaldon’s admission in December that he was in fact a British spy caused huge embarrassment for British prime minister Tony Blair, the North’s controversial police service, and the ombudsman Nuala O’Loan, all of whom had previously denied the raid served a political purpose.
The key questions today are who killed Denis Donaldson, and why.
It may be helpful to apply the rule of Cassius, the Roman judge, still a principle of criminal investigation today: cui bono fuerit — who benefited?
Not the Republican Movement, which had already caught Donaldson, held a press conference and released him.
Possibly someone he betrayed over the past 20 years who is now a dissident republican.
And certainly Britain’s intelligence services, who no longer fear Donaldson will further expose their interference in the democratic process.
Irish unionists also gain; indeed they have already seized upon the killing, blaming the IRA and claiming it as yet another excuse to avoid sharing power with their Catholic neighbors.
The investigation into his killing will likely be a long and complex one. It should run parallel to a public inquiry into Stormontgate.