The executioner walks into the venerable, dusty, fin-de-siècle office of the Association of 21 December. The organisation, so named to commemorate the first day of the December 1989 revolt in Bucharest, is suing the Romanian government for the truth about the still opaque mysteries of the revolution which overthrew communism in Romania 20 years ago. As with many of the small people who make epic history, the executioner's story emerges slowly.

Dorin-Marian Cirlan is one of the three-man firing squad which killed the megalomanic communist dictator Nicolae Ceausescu and his wife Elena on Christmas Day 1989. Cirlan emptied the magazine clipped to his Kalashnikov AK-47 into the couple's bodies from near point-blank range, after they had been captured by revolutionaries. The moments after the execution were famously televised, broadcast to Romania and the world as evidence that an era had ended, that the most turbulent and violent of the revolutions which collapsed communism across Eastern Europe during 1989 had achieved its immediate objective.

But the Romanian revolution was not what it seemed - that is, a popular revolt against the dictator in which the people were joined by the army. Ever since, the man who apparently led the insurgency and succeeded Ceausescu, Ion Iliescu, has frequently been accused of staging more of a coup d'état than an uprising. As the strange story of Dorin-Marian Cirlan suggests.

I met Cirlan in May. Dressed in a black bomber jacket, blue polo shirt, black trousers and polished shoes, Cirlan has a thick set, stern, determined face. "I sat on Ceausescu's body after killing him, because there was nowhere else to sit in the helicopter. It was probably more comfortable than the seats," he told me. "He was still warm, and his blood spread on to my camouflaged trousers. The armed forces never paid to have them cleaned."

Will this, then, turn out to be the narrative of a professional but impenitent (if not callous) paratrooper carrying out instructions? Not at all. "Yes, I did feel as though I had played a part in history. I knew all about the French revolution, the guillotine, and felt that I had done something similar. But I was not comfortable with it. The trial lasted 1 minute and 44 seconds, the execution less than 10 minutes. I had been trained as a commando to fight for this country. Ceausescu was my supreme commander-in-chief, and I had been trained to protect him at all costs, not to kill him."

Cirlan's narrative ploughs its remarkable furrow for the first time in English (he has written a book in Romanian), with the military precision one would expect from an elite paratrooper. And yet it ends with the plea of a man curiously isolated from a society supposedly now liberated from the dictator he killed.

For two years, in the late 1980s, Cirlan had been a member of an elite paratroop commando unit. On the morning of Christmas Day 1989 his unit was told that volunteers were needed for a "special mission" categorised Zero Degrees - "which signified that one did not know that one was going to return". Eight commandos were flown in two helicopters, "commando style", says Cirlan, "at 150kph, but only 15-30 metres above the ground, so as to fly below radar, and in a zig-zag motion." The destination was a stretch of land near the Steaua Bucharest football stadium. "We were met by a convoy of an APC [armoured personnel carrier] and several cars carrying senior officials and General Victor Stanculescu, whom I knew from the TV was the revolutionary deputy minister of defence, and whom I had seen on television as part of the National Salvation Front."

The helicopters then flew on to Tirgoviste, "escorted by a strong air defence - five helicopters in all, flying only 10 metres above the ground, told to show the yellow scarf, signifying 'Heroes without Honour'. Then we landed."

Cirlan hunches forward, elbows on knees, kneading his hands together. His shape wouldn't get him into the paras now, but you can tell that two decades ago, this was a man of imposing physique. "First, General Stanculescu said he needed four people from each helicopter, and that what would happen would be done without badges, and we must be armed with grenades and knives as well as our weapons. 'My dear comrades,' he said, 'I have trusted the paratroopers long, and now I trust your commitment to the revolution.' He said there would be 'an exceptional military tribunal' to 'apply the law of the National Salvation Front, to try and condemn the couple who have done terrible things to the Romanian people. Do we proceed together to the end?' he asked, and I thought: 'What end?'

"Then the general said: 'If the sentence is death, are you ready to carry out that sentence?' We all, like a choir, replied 'Yes.' He was unhappy with that, and asked anyone willing to carry out the sentence to step forward. We all stepped forward. Then he appointed three of us, a captain, me [a petty officer] and a sergeant. We were ordered to get everyone out of the building, guard the door of the courtroom and kill anyone who tried to break in. The captain was shown the place where Ceausescu would be killed if he was given the death sentence, and we were told to empty a whole magazine of ammunition into him."

Ceausescu arrived at the court and, according to Cirlan, he panicked: "He didn't know who we were. 'Are you Romanian?' he asked. 'We are with the general,' I answered. We had to stand guard outside the trial, but could hear perfectly well. When the sentence was read, it was a terrible moment. 'Appeal in 10 days,' said the voice, 'sentence to be carried out immediately.' I was about to kill the president, but I told myself to act without thinking, especially from any judicial point of view. General Stanculescu took a stand. He ordered us to tie them up, take them to the wall, shoot him and then her."

Then the Ceausescus appeared. "They were whining like children," Cirlan remembers. "'We can't be killed like dogs!' he cried, and looked at us. 'We're going to be killed like dogs!' It was a hard moment for all of us. Then she said: 'If you are going to kill us, then out of respect for our love for each other, don't kill him and make me watch. At least let me die along with my husband.' And the general ordered: 'Take her to the wall with him.'"

At one point, Cirlan said, "It was so hard to look at them, we turned away. They were placed against the wall. We knew who they were, but I suddenly saw this human face - he looked so puzzled by it all. Then he looked straight into my eyes and shouted: 'Long live the socialist republic of Romania! History will avenge me!' And he started singing a fragment of the 'Internationale'. That is when the order came, and all three of us fired, from the hip. We shot him while he was singing. We shot them from a distance of one metre, maybe even 50cm. We'd only emptied half the magazines before they were pinned to the wall, dead. The impact of bullets into her was so strong that she went like this..." and Cirlan, seated until now, gets up to demonstrate how Elena Ceausescu was blown diagonally and upwards against the wall. He then returns to the black faux-leather sofa.

"We were like robots," he said. "We did everything very quickly. Ever since then all I have wanted to do is to study philosophy and law. To understand what I did, legally. I was a petty officer obeying the orders of a general, who killed a man after a fake trial. I killed Ceausescu on Christmas Day, but the decree setting up the court was signed on the 27th, by which time he had already been dead for two days. Only that night did they show the bodies on television. None of our movements that day left any paper trail at all. The man I killed was the dictator they all said they hated, but they ostracised me forever afterwards, all the same. Iliescu does not like me, the press blamed me in some way for the unfairness of the trial and for firing all my magazine. The politicians kept their distance from the whole thing, and I was sacked by the Ministry of Defence in 1998."

The fixed, recollective expression in Cirlan's face changes. He becomes sorrowful in a defeated, baffled way. "I am now a lawyer, but cut off from society, living on the edges, a black sheep who gives legal advice. And it is a gift of God that I am alive to tell the tale."

With that, former Petty Officer Cirlan, the tyrant's executioner, rises, shakes hands, and leaves the office.

To shake the hand of Cordruta Cruceanu outside the national gallery of art in Bucharest is to do so across 20 years since we first met. In 1989, she was a curator in the museum while a battle raged among the paintings. One day, as we walked the gallery floors, the view across the cobbled square through a large opening blown in the elegant wall by an artillery shell was of tanks grinding over charred debris, nervous young soldiers - with flowers placed in their helmets by the people - returning the occasional crack of sniper fire, and crowds come to gawp at the fallen fortresses of the Ceausescu regime. It looked like war from another time, on black and white newsreel; a week had passed since Ceausescu's execution, but it had taken days to subdue the stench of gunsmoke, shellfire and scorched masonry.

Beneath our feet as we walked were the incinerated remains of the museum's inventory - paintings were pitted with bullet holes, the canvases strewn like corpses in a morgue. "As you can see, there was heavy fighting here, the Byzantine room," Cruceanu said. "And a lot of shots were fired in the 19th-century national school, where we think our army had come in. But the Securitate [Ceausescu's secret police] must have come through the forbidden corridors from the palace, or a skylight"... and we ascended to the third storey... "so that most of the shooting was here among the European paintings, of which I'm the curator."

My notebook recorded that there was damage to Boccaccini's Samson Breaking the Pillars of the Temple, Gentilleschi's Mother and Child and Rembrandt's A Man Begging the Forgiveness of Esther. At the end of the gallery was a piano, lightly coated in snow which had drifted in through the holes punched by shellfire and the top of a dome that had been blown off. Cruceanu raised the lid and played a few notes of, I think, Bach. "It works!" she said. "So you see, there is hope."

In May, Cruceanu and I met again, in spring sunshine. Now 55, she told me that the gallery held an exhibition of the damaged paintings in 2000, but of the events of 1989 she said, "We still don't really know the full truth, and I wonder if we ever will. There are too many people alive in whose interests it is that we never know who was fighting who, and why. What we do know, though, is that it was all theatre, to a degree - that it was staged."

Although the Romanian revolution was the most dramatic of the insurgencies against communism that swept across and united Europe 20 years ago, it was also the most mysterious, dichotomous and duplicitous. At the time, the world watched a mass uprising against the Ceausescu regime: first in Timisoara, then memorably at a mass rally Ceausescu held in Bucharest, where the crowd began to jeer and boo him. Shortly afterwards, he and his wife Elena were executed. However, it took some time before the revolutionary leadership under Ceausescu's challenger, Iliescu, could subdue the Securitate loyal to the tyrant. The violence was terrible and the deaths, over many days before and after the execution, remain incalculable to this day.

No one doubts that there was a popular and bold revolution, on the streets, by the people. But what is still not explained is who was manipulating them, and why. Who was shooting at who? And what were Iliescu, his faction in the communist party, and generals loyal to him doing behind the scenes? Lingering still, after two decades, is the appalling notion that the fighting was fabricated and that the revolution was a facade.

"Of all the hundreds of speeches Iliescu made and has made since then," recalls Cordruta Cruceanu, "the one that sticks in my mind was when he said: 'In a country like Romania, it was impossible to have a revolution, so it had to be staged.' That is the closest he has ever come to admitting what almost everybody believes, or knows, to have happened."

The fall of Ceausescu was announced, unforgettably, by Romania's leading actor, Ion Caramitru, on television from the national TV headquarters, which had been occupied by the democratic revolutionaries, of whom he and the dissident writer Mircea Dinescu, with whom he appeared on screen, were the most prominent. I remember days and nights in the TV centre - which was under fire from what were thought to be loyalists to Ceausescu - meeting Caramitru during the endless and open debates about the future of the nation and what to broadcast about it, in a mood which seemed to combine 1968 with something more fearsome. Caramitru has since become a screen star and one of Europe's greatest Shakespearean stage leads - notably Hamlet and Lear - but he never left politics: he left Iliescu's National Salvation Front when it turned itself into the ruling political party, and was minister of culture in the rival coalition government between 1996 and 2000.

Last month, after a striking performance of Edward III at the national theatre of Romania, of which he is the director, Caramitru invited me up for wine and reflection in his splendid, book-lined office. "I was gesticulating with the officer of an APC after two days on the streets - 21 and 22 of December," he recalls, "and asked him if he was the commander. The officer replied, weeping like a child, that if Ceausescu had fled, we, the people, must be the commander, so that 'You must be my commander now.' The whole thing was surreal:

I said: 'OK, let's take your APC to the television station, then,' which we did - the people marching behind - and went in. We got the transmission organised and then we made the announcement: 'You are free, Ceausescu is gone.'

"There had been a revolution by the people, but the people had been tricked," he says. "We were romantics, we had no relationship with those in power. Within a year, it was beyond doubt that one faction had simply removed another faction, probably in direct contact with Moscow, where Gorbachev had realised that Ceausescu's system would implode. The institutions which had run the country remained intact, albeit with another name. Tragically, more people were killed after the execution of Ceausescu than before. If I were Iliescu and believed in God, I'd fear God's judgment regarding the dead."

The falsehood bequeathed a strange hybrid: a country which embraced the capitalist market system, but was still run by the old guard. The legacy is reflected in a report last year by the European Union, which admitted Romania only to label its new member the EU's second most corrupt country, after Bulgaria.

There was an attempt to clean up the system, by the current president, Traian Basescu, but such was the resistance from parliament that, as one of the Justice Ministry's assistants during that period, Laura Stefanescu, puts it, "Our only victory was that there was no defeat, and that the immunity of the political class did not become even stronger. Romania," she said, "is like the international banking system, throughout an entire society: rules exist only for honest people; there are no rules for those who are corrupt."

The corruption results not only from the falsehood of the "revolution", says Mattei Paulin, an investment banker raised abroad but who repatriated after 1989, but in "the west's complicity in the privatisations" that followed. "Before 1989, there were various factions within the communist system," Paulin told me. "Now, after what I call a 'regicide' rather than a coup d'état, let alone a revolution, those same factions exist in what appears to be a market system, but is in reality a rotten state which sold off such assets as the national bank and Petrom [the state oil company] and its substantial drilling interests for a fraction of their value, to companies from France, Austria and other countries, simply to protect their own political positions. The western powers and corporations happily and knowingly played along."

The iconic flag of 1989, the Romanian tricolour of blue, yellow and red with a hole cut where the communist symbol was, still flies in the magnificent hallway of the offices of the Association of 21 December, its old wooden walls covered with pictures of the burning art gallery, other unforgettable scenes from those days, and portraits of the dead. From here, Doru Maries's association has been suing the Romanian government (and now does so through the European Court in Strasbourg) for a truthful account of what happened in 1989.

A former professional footballer, Maries was among those in the democratic opposition who occupied the Politburo building as Ceausescu fled it (it was on the balcony of the Politburo that Iliescu appeared to the crowds). Maries was among those who grabbed a gun as he entered, only to offer it back after he realised what was happening. "A group was at one point sent down to the basement to confront Securitate 'terrorists'," he said. "Another was sent with the same order, but down another staircase. They ended up shooting at each other. What we are claiming is that there were no 'terrorists', that the whole thing was fabricated, and the deaths unnecessary."

Maries produces documents filed in court, which he says show Iliescu ordering the communist party apparatus to continue collecting subscriptions, and for its officials to remain in place. "For 20 years," he said, "we have faced a wall of silence, and continue to do so."

When the democratic movement in Romania began to sense that things were not as they seemed, demonstrations against Iliescu took to the streets. Between early 1990 and 1992 they were routinely attacked by what became known as the mineriada - violent interventions by coal miners from the Jiu Valley. The miners were mobilised by union leader Miron Cozma, who was ferociously loyal to Iliescu, and ostensibly to the men he represented. On one occasion, miners ransacked the headquarters of conservative parties; on another, they cracked the skulls of demonstrating students.

Much has been written on Cozma's escapades, but little on the duality of pride and shame in the story of the Romanian miners, who always held a special place in communist iconography, even though the drab apartment blocks in which they lived were not allowed chimneys in case they were tempted to warm themselves with what they mined.

There was another minerad in 1999, this time in defence of miners' jobs, as the pitheads began to close. The impact of pit closures on the Jiu Valley is catastrophic, and a parable of the price Romania paid for liberty 20 years ago, when it exchanged the iron fist of communism for the ravages of the market. Or, as some would argue, combined the worst of both.

Miron Cozma was jailed for his part in the miners' demonstrations against the pit closures, but pardoned by the re-elected Iliescu and released in 2004. Today, his brother, Tiberiu, is the deputy leader of the miners' union. "What we have seen," Tiberiu said, "is the politically motivated destruction of the Romanian coal industry, as agreed between the government and the IMF in 1997. When you were last here, 47,000 men worked in these mines. There are now less than 11,000."

In an upper region of Vulcan called Dallas (out of mockery), sewage runs in the open, children play in filth and squalor, idle families crowd the balconies of the peeling apartment blocks, where the lifts have been jammed and used for storage. Ion Nelu tries to provide for his wife and three children. Laid off from the mine in 1997, he does this, he says, "by maybe finding scrap metal, in the closed mines, or some coal to steal. Or else by foraging around the forest for mushrooms to sell."

To the north is Aninoasa, an entirely dead town since the pit was closed. As we drive through, a group of men are loading scrap metal, baths and toilets ransacked from the closed mine and empty houses on to a truck. "Don't stop," I'm told. "Very dangerous." Watching from a bench is Szebiges Lajos, who once worked in the mine. "It was always hard," he says. "Before, you had the secret police on your back, but at least we had work. Now, absolutely nothing. Why would anyone want to close down a perfectly good mine?"

Coal now comes to Romania from Russia, the Ukraine and South Africa. Illie Martin, the former manager at the Vulcan mine, now runs a company with a contract to clean the town. He said he had tried to move from management to lead the union, but was elbowed out.

At the other end of the Carpathian mountains, it is a similar story. Behind the Danube port of Galati stands what was once an awesome steelworks. In 1989, the state-run Sidex was the largest steelworks in Europe, producing the widest range of specialised steel on the continent. The site now belongs to Lakshmi Mittal, the world's biggest steel magnate and Britain's richest man. According to the leaders of Solidarity, a new, independent miners union, Mittal is "amputating the factory, limb by limb". It was for "downsizing" like this that Mittal's headquarters in Luxembourg was besieged by rioting steelworkers last month.

"At its peak, Sidex employed 40,000 people," said Ilinca Bianocu, the female president of Solidarity. "When Mittal bought the works there were 27,000. Now we are down to 12,500. The government sold it for nothing, and now the new owners claim it is not competitive, so they will not invest," she said. "And I wonder why. The demand for steel increases, the price of steel rises, but the jobs decrease.

We see no reason to run down this pearl of Romania, unless it is to move the entire industry to India and China."

Back in Bucharest, after walking through the now completely refurbished art gallery, Cordruta Cruceanu chooses a café she likes in a restored building from Romania's great inter-war days of cultural proximity to Paris. "They have managed to do some lovely things to the old cafés," she observed, recalling how she used to wander through the ruins of this now smart place to admire a statue of a dolphin. Now, though, "I work differently," she said, "to try and contest the values in this country which have become, frankly, screwed up. I'm involved in a project in Sofia, getting children away from their computer screens and into the city, to look at how they relate to it, to what in the Renaissance was called the Piazza, the urban space, physically, artistically, socially."

Cruceanu believes that "with hindsight, Romania was more vulnerable than any other communist country to the myth of the west as material paradise, to mall culture and measurement of success by what kind of mobile phone you have. It's particularly strong here, perhaps because it all happened so suddenly, even to the educated classes. A lot of damage has been done, both to Romania and to the west, as we now see in this crisis: because the west began to believe some of our illusions about itself - in our false expectations of what it seemed to promise, back then in 1989. Which feels at once like another lifetime, but yesterday."