ALONG Tripoli's baking hot streets it drifts on the breeze and creeps up unexpectedly.

In the city’s notorious Abu Salim prison it lingers eerily behind its concrete walls and heavy steel gates. So overpowering is its presence at one of the killing grounds used by the Libyan Army’s dreaded Khamis Brigade, that it makes you gag with nausea.

They say that of all the senses, smell can trigger recognition, emotion, fear, like no other, and that is certainly true when it comes to the odour of death.

Tripoli has been no stranger to death these last months. The corpses that carry the city’s ominous stench have been found in warehouses, back streets, and in the liberated detention centres of Colonel Muammar Gaddafi’s secret police and military. This is the real and grotesque cost of the people’s revolution that overthrew his dictatorship.

Libyans, of course, are no strangers to the brutal excesses of Gaddafi’s 42-year rule. Hussein Elshafa spent 12 of those years in a cell at Abu Salim. His crime, way back in January 1989, was to talk of political reform to his fellow college students and be found reading a book on humanism.

For that, Gaddafi’s Mukhabarat or secret police came to his family home in the small hours one morning where they bound, blindfolded and arrested him.

For the next decade Elshafa’s family did not set eyes on him. Yet he was one of the lucky ones. Most who entered Abu Salim never left alive. A fully served-out life sentence or the death penalty was almost always their fate. Hussein Elshafa was to witness hundreds die.

“It was a Friday, June 28, 1996, I will never forget it,” he tells me. “By then my cellmates and I were trustees in the prison and were separated from the other inmates after a riot had broken out over the conditions we were enduring,” he recalls.

What he was to witness in the hours and days that followed was the systematic massacre of as many as 1270 prisoners as they were gunned down inside Abu Salim.

“These cells here were full to capacity with bodies,” he explains, pointing at the heavy steel doors that now lie open, the airless claustrophobic cells empty following the prison’s liberation by rebel fighters in recent days.

“The jailers brought in a bulldozer and dug a big hole, a mass grave right here in the grounds and started filling it up with the dead.”

As the corpses of the prisoners were disposed of, those soldiers who carried out this task, their hands caked in gore, ordered Elshafa and the other trustees to clean the blood from the rings and watches they had robbed from the dead.

Having recently returned from exile in the United States to join the rebel advance from the mountains towards Tripoli, Elshafa says that, like many survivors of Abu Salim, he needed to come back to see for himself the final days of the hell-hole in which he was incarcerated for so many years.

Now he is looking to the International Criminal Court (ICC) to launch an investigation and bring to account those within Gaddafi’s regime responsible for the atrocities he witnessed and the “living nightmare” he endured all those years ago.

His wait for the ICC’s response, however, may well be a long one, for Tripoli is full of much more recent and pressing atrocities for which survivors are demanding accountability and justice. Fiercely loyal to Gaddafi’s youngest son Khamis, the Libyan Army’s 32 Brigade that bears his name was the nation’s most feared military unit. A few days ago I passed under the bullet-scarred archway at the entrance to its headquarters in Tripoli that stands topped with a giant eagle, the brigade’s symbol.

Targeted heavily by Nato’s war planes, the main command buildings that sit within this fortress compound the size of a small town lie smashed by hi-tech bombs.

A long tableaux-style mural running adjacent to a parade ground shows Gaddafi, god-like, looking down on his soldiers, sailors and airmen victoriously putting their enemies to flight. Gaddafi’s nose has been shot away by bullets – this and the spatter marks of rocket-propelled grenade explosions tell another story of the real battle that his elite troops faced here in the heart of their headquarters.

Outside one administrative block ignored by the looters who carted off fridges and furniture lay copies of Gaddafi’s infamous Green Book that contains his meandering and often bizarre take on the world.

Inside the building, charts and maps lay strewn across the floor among the broken glass and empty shell cases. On one desk sat a half-drunk cup of coffee, on another a military manual in Russian and a report outlining a joint training exercise between the Libyan Army and that of Serbia and Montenegro. There were also brochures and manifests for arms purchases from a company based in South Korea and personnel files marked Confidential. In these files, handwritten notes told of the individual allegiances and loyalties of certain officers. Even here in the Khamis Brigade, no-one it seems was ever fully trusted.

But nearby there were other more visceral secrets that the Khamis Brigade had tried to hide.

Rebae Fereg Kashot lives only a few hundred yards from the Khamis HQ. Every day during the breaking of the Ramadan fast he would take dinner to an old man who lived right next to a compound that sat behind the headquarters. That same old man had begun to tell him of what he was hearing and seeing.

“He said he heard shooting every night, and people screaming,” Kashot recalls. Then on Sunday, August 21, the sound of automatic rifle fire could be heard for up to half an hour. Kashot himself approached the compound but was stopped by a soldier who he described as one of Gaddafi’s mercenaries from the West African country of Chad.

In the days that followed, he and other local people uncovered the terrible evidence inside the compound of one of the worst war crimes to date during this six-month Libyan uprising.

“Can you smell it?” asks Kashot. “Look at these flies. Have you seen what is inside there?” His voice quivers with emotion and he is still clearly traumatised by the gruesome discovery he made a few days earlier. What lay inside the corrugated metal outhouse were the charred remains of 53 men who had been imprisoned and often tortured here for weeks and months.

Peering in through the door the floor was a blanket of silvery grey and black cinders though bones and skulls remained clearly visible. The stench was appalling.

This was all that remained after the Khamis Brigade soldiers had machine-gunned their prisoners and thrown in grenades before hurriedly trying to dispose of the evidence by burning the hut down.

“You see, this is Gaddafi, this is what he does,” said Kashot, swatting away the swarms of bloated flies that buzzed around us.

Nearby, he led me to a box van where some of the prisoners had been kept with virtually no food and water for up to 10 days in Libya’s oven-like heat. With no light whatsoever, survivors who had crawled out from beneath the heaps of bodies gunned down in the shed told Kashot that the only way they could tell the time of day inside this vehicle was by the change of temperature. They told also of efforts by some of their fellow detainees to escape, how they were then chased and shot down by Chadian mercenaries as they tried to climb the compound walls into neighbouring backyards and slip away.

At one point, as the revolution began to take hold in Tripoli and rebel fighters closed in, there were as many as 150 people held here in the Kalit Alforgan district of the city.

Clues to the fate of those whose bodies have yet to be recovered may lie in the presence of a bulldozer and brand new refrigerated container that had been delivered to the compound just days before rebels overran the area.

Locals, including Kashot, believe many are still buried beneath the compound grounds and that their Khamis Brigade killers were making an attempt to dig up the damning evidence and transport the remains by container elsewhere when the rebel advance interrupted their gory work and forced the Khamis men to flee.

Not all of Gaddafi’s henchmen made it out of Tripoli, however. On Friday, at the Matiga hospital in the west of the city, I watched as a group of wounded pro-Gaddafi fighters were brought in for medical treatment under rebel escort.

Dressed in camouflage fatigues and speaking English with a distinct Mancunian accent, one of the rebel guards, Hatem Shabil, told how the men had been captured shortly after the fall of Gaddafi’s Bab al-Aziziyah fortress compound.

“After they lost the war in the streets, they worked as snipers climbing up into buildings and killing people, including women and children, on the express highway that runs near Abu Salim district,” explained Shabil.

“But we will get them all, street by street, house by house, room by room, we will hunt them down,” Shabil insisted.

He confirmed, too, that rebels knew of other pro-Gaddafi “sleeper cells” still in existence across Tripoli, and that in neighbourhoods like Abu Salim, one of the poorest in the capital and where as many as 70% of the men were soldiers in the Libyan army, supporters of Gaddafi armed with Kalashnikovs and other weapons are still hiding.

Only a few days ago a massive arms cache was found in this area, and earlier last week during my visit to Abu Salim prison, this lingering support for Gaddafi was brought home when a woman standing in her doorway, audaciously shouted “Long Live Muammar” as our car drove past.

Where exactly Gaddafi is now of course remains a question of intense speculation, with some rebels speaking of him being holed up near a place called Bin Jawad, while others insist he has fled south to Sabha near the border with Chad, where so many of his mercenary soldiers originate from.

Here in Tripoli his rule may be over but his legacy continues to intrigue as well as horrify many Libyans. Last week at his Bab al-Aziziyah compound, I stood along with many ordinary people on the balcony from which Gaddafi made so many of his defiant speeches and denunciations.

In the bombed-out rooms off the balcony lay some almost surreal clues to the character of the man who brought so much suffering and terror to his people: a book on witchcraft; bathroom tiles decorated with Disney characters including Snow White and the Seven Dwarfs; ostentatious furniture. And all this within a few miles of places like Abu Salim and other secret police jails where unspeakable things happened. Gaddafi may have gone but many Libyans will not rest easy or believe they are truly free of his grotesque legacy until he is either killed or captured.

Twelve years inside the hell that was Abu Salim prison have left the likes of Hussein Elshafa in no doubt about what they would like to see become of the former dictator.

“Who cares about the million dollar reward?” he tells me. “I’d happily settle for Gaddafi’s head.”