His nearest neighbour, in the remote lane outside Glenties, was two kilometres away.

There was no chance to reach for his mobile phone. He may well have known his assassins. They could have been among the thousands of republicans he'd met moving in Sinn Fein/IRA circles over 40 years.

If he begged for mercy, it was futile. They were never going to change their minds.

This was one situation that Denis Donaldson, charmer and raconteur, couldn't talk his way out of. In vain, he raised his right arm to protect himself as the gunman took aim. His hand was almost severed in the blast.

In close combat situations, a shotgun is deadly. It rips you to shreds in a split second. Later, a female passer-by apparently noticed the broken window and rang gardai. But until then, Denis Donaldson lay on the floor of the pre-famine cottage, hidden in the Doochary hills.

It will be no comfort to his family but other informers have met even more horrific deaths: tortured, then dumped naked by the road, covered with a bin-bag.

In other parts of Donegal, wild daffodils light up the landscape and hedgerows blaze with the colours of spring. But not much grows in the fields around Donaldson's abode. There's a magnificent, cruel wildness to the place.

"Denis loved it up there, " says veteran republican and former Sinn Fein Assembly member John Kelly, recalling conversations with Donaldson before he was outed as a spy.

"He was always talking about heading to the cottage, lighting a big fire and spending the night in a sleeping bag. He was as excited as a boy scout going to weekend camp.

He loved the whole idea of roughing it, drawing water from the well, going back to nature."

Donaldson, 56, was Sinn Fein's chief administrator at Stormont, so Kelly knew him well.

"Sometimes, I'd look around and wonder who the British agents were in Sinn Fein.

Denis never crossed my mind.

"He was there under Gerry Adams' tutelage, so he was trusted. He was very affable . . . not intellectual, but smart, in a streetwise kind of way. He was meticulous about his work.

"At social functions, he'd never take more than a few pints. Denis displayed no excesses in mood or habit. He must have been on big money from his British paymasters but he was never flash. He drove a 10-year-old car. He was a thrifty kind of fellow, always counting his pennies."

Kelly recalls Donaldson's courtesy to Stormont staff, most of whom were Protestants: "They'd often be treated with disdain by unionist politicians, but Denis went out of his way to be nice to them. He saw it as good PR for Sinn Fein. Every year, he'd invite the cleaners, canteen staff and civil servants to our Christmas party. He'd go and get the sandwiches, biscuits and buns himself."

Gerry Adams downplays his relationship with Donaldson, stating he had "very little contact with him over the years in terms of our day-to-day business".

Kelly says that's untrue: "Denis Donaldson was Gerry Adams' eyes and ears at Stormont. We all knew that. For whatever reason, Gerry Adams is rewriting history."

The Sinn Fein president has unreservedly condemned Donaldson's murder. It's not in any way to justify the killing to say that Adams' response is unrepresentative of the feelings of republicans the Sunday Tribune contacted.

"Ordinary republicans aren't shedding any tears, " says Kelly. "There's a certain inevitability about what happened Denis.

He was a husband, a father, and a grandfather. I sympathise with his family, but goodness knows how many republicans went to jail or their graves as a result of his betrayal."

That "betrayal" hurts more because Donaldson joined the IRA in the mid-'60s, when it wasn't the fashionable thing to do. He grew up in the Short Strand, surrounded by loyalist east Belfast, where life was tough for Catholics.

In 1971, he was sentenced to 10 years in Long Kesh for explosives offences. It was there he made friends with Bobby Sands.

Released after five years, he became involved with Sinn Fein but was also a senior IRA intelligence officer, travelling the world to meet organisations like the PLO and Eta. The information for his handlers was invaluable.

Donaldson's pleasant, unassuming nature meant he was privy to countless confidential conversations over the years. No one ever worried about his presence. "Ach, it's only Denis!" they'd say.

He claimed he became an informer at a "vulnerable time" of his life in the 1980s.

There are rumours he was blackmailed by the security services after he was caught stealing from Marks & Spencer. But that's an unsatisfactory explanation as to why he continued spying for decades.

The only talk in republican ranks was of his womanising. He was notorious, even showing up one night with a bottle of wine at the home of lesbian Belfast community activist, Marie Mulholland. She told him she "didn't vote that way". He said he knew but thought it worth a try. It all ended in good humour and they became friends.

Republican sources say police raiding a north Belfast woman's house found him in bed with her. A female Sinn Fein worker at Stormont complained when he accessed porn on his office computer. But such displays of crudeness were rare. Women generally liked Donaldson.

He was married with three children. His wife Alice remained devoted, even after his outing as an informer. "She never once thought of disowning him, " says a family friend. "She just loved him in a very old-fashioned way." Sources say she visited her husband in the cottage but it was too uncomfortable for her to sleep there, so she'd stay overnight in Letterkenny.

The family's west Belfast home has been put up for sale in recent weeks. Viewers noticed photographs of Donaldson still on the walls and a stack of James Bond DVDs.

In the early 1990s, Donaldson was sent to run the Noraid office in New York. Colleagues recall days he walked all the way from his apartment in the Bronx to Noraid's Manhattan office just to take in the sights of New York.

He visited jazz clubs in Greenwich Village and enjoyed eating in ethnic restaurants.

He clashed with Noraid's publicity director, Martin Galvin. "I liked him at first but then I increasingly found him to be a fraud. He lied while smiling into your face, " says Galvin.

Will Galvin condemn his murder? "Denis Donaldson treated his posting to New York as a holiday. His apartment and expenses were paid by republicans while he was also obviously in the pay of the British. He toured the country, staying in people's homes, taking their hospitality, while betraying them.

"His information undoubtedly condemned republicans to jail or death. There's a tradition of how informers are dealt with. I've some degree of sympathy for his family but I won't offer a hollow condemnation of his killing."

Ex-IRA prisoner Paddy Murray from Co Antrim isn't unhappy about Donaldson's killing: "He was a spy and a traitor who deserved to be shot. The IRA green book says touts are to be executed, it's as simple as that. There is no negotiation . . . they get whacked. I sympathise with his family but he knew what he was doing. He wasn't a £10 tout.

Denis fancied himself as James Bond."

An ex-IRA prisoner from west Belfast, who wishes to remain anonymous because he knows the Donaldsons, goes even further:

"Shooting was too good for him. I'm disappointed he wasn't tortured."

To those outside the republican movement, such views are heartless and immoral.

But the ruthlessness of life in the IRA has deep roots. Michael Collins actually claimed the killing of informers made the air sweeter.

"There is no crime in detecting and destroying, in war-time, the spy and the informer.

They have destroyed without trial. I have paid them back in their own coin, " he said.

Former IRA prisoner and writer Anthony McIntyre disagrees with those who justify Donaldson's murder: "During the war, I supported the killing of spies. We joined the IRA, not a knitting club. But the war is over so there is no reason to kill informers. What Denis Donaldson did was inexcusable but he was banished from normal society. A social death was imposed on him. There was no need for a physical death."

Former IRA hunger striker Marian Price, now a member of the 32 County Sovereignty Movement, says Donaldson was "a traitor who knew the risks". Like other republicans, she says the information he provided his handlers meant jail or death for his friends.

"Long-term informers at a leadership level are entirely different to those who break during interrogation. Donaldson wasn't forced for 20 years to be an informer. Had he wanted out, he could have got out.

"He could have staged an argument with a leading republican and told the Brits he'd been sidelined because of it. He could have told the Provos he wanted to step aside because he was suffering stress or not in good health. He kept informing because he wanted to."

Price claims it's "too simplistic" to say Donaldson informed for the money: "Spies have a faulty gene. It takes a certain type of person to live a lie, to form deep friendships and share confidences with people and then betray them." She says she has "no problem" if Donaldson's killing means other informers now "sleep less easily at night".

The most puzzling aspect is why a shrewd operator like Donaldson chose to remain in Ireland. Sources say he received assurances from the Army Council that he was safe. But so did informer Frank Hegarty after he went into hiding in England. A fortnight after returning to Derry in 1986, he was found shot in the head on a road, his hands tied behind his back and black insulating tape round his eyes.

Donaldson evidently believed such a fate was unlikely for him in the post-ceasefire climate. Some suggest that maybe, subconsciously, he had a death-wish. But his family's loyalty despite everything, and his self-centred nature and survival instincts, make this unlikely.

He wasn't completely outcast. He was seen socialising in a bar in Crolly, Co Donegal.

Unconfirmed reports put him, for whatever reasons, at a Sinn Fein reception in a Dublin hotel, on 26 January.

Perhaps leaving Ireland was psychologically too traumatic for Donaldson. He didn't want to be a Sean O'Callaghan, pontificating on the IRA from the streets of London.

He declined police protection. To accept would have emphasised how far he'd strayed from the republican fold. He stuck tenaciously to the Sinn Fein script that there was no spy-ring at Stormont. He gambled that playing Provo rules would save his life, that promises would be honoured, and that no other republicans posed a threat.

Over the years he surely discovered other agents who are still within republican ranks.

He could well have guessed the identity of the other agent for whom, it's likely, he was sacrificed over Stormontgate to protect. Did he swear an affidavit to a solicitor, detailing this, as an insurance policy against murder?

Sinn Fein claims that during questioning by the party after his outing, Donaldson refused to disclose details about his spying career. Given his vulnerable position, that seems most unlikely, but it suits Sinn Fein because now no explanations are required for the republican base about Donaldson's activities.

Gerry Adams says Donaldson claimed he earned £40,000 for spying. "That's two grand a year. Catch yourself on! Denis wouldn't have put himself at risk for that, " says a former friend.

One theory is the Provos took his savings as part of the deal that he live. Denis Donaldson, of all people, should have known that, in the murky world of spies and paramilitaries, there can be no such thing as trust.