Halfway up a mountain of rubble, on the site of what was once a three-storey apartment block, you started to hear the screams. A woman was buried underneath the concrete, apparently with her entire family. She had been there five days, and now that a search-and-rescue crew had finally arrived, she was in hysterics.
There are several people alive underneath. We think at least five," said Marqueli Louradel, who was leading a team of local men hacking through the concrete with sledgehammers and pick-axes in the Canape Vert neighbourhood.
"Six children lived there. But it's impossible to tell if they all survived. When we stop digging or making a noise she screams. She's terrified we will give up and walk away."
Mr Louradel, a local volunteer wearing a bright orange baseball cap to identify himself as a rescuer, rather than a looter, estimated it would take another three hours to get through the first concrete panel leading to the air pocket.
If more debris was in the way, it could take longer. "We're not giving up, though," he said. "We'll stay here all night if we have to."
Across Port-au-Prince, identical scenes are being played out, as Haitians and foreign teams made a frantic final effort to save victims trapped in the rubble. They don't have long left. Already, most of the survivors are terribly dehydrated, after almost a week underground, and many of the people they were originally trapped with are already dead.
At the municipal hospice just a mile from the airport, 85 elderly people were starving to death yesterday.
One man, 70-year-old Joseph Julien, had already died for the lack of food, and his body still lies alongside the living on a mattress outside the collapsed building. Without help, an administrator said, "others won't live until tonight".
Mr Julien is part of what is now a momentous tally. Government officials now say that 100,000 is a minimum death count, and the toll could be twice that. Some two million people across the country need emergency relief. Foreign aid is starting to arrive on the streets, but only in dribs and drabs.
I saw three rubbish trucks trundling through the streets picking up bodies, and several large fires in riverbeds, where the authorities are attempting to dispose of some of the mountains of rubbish. But meaningful quantities of food and medicine are still failing to reach the places they are most needed.
The situation is hardly less bleak in the country beyond the capital. And isolated survivors in the rest of Haiti are crying out for help that has so far been unable to reach them. In Leogane, a port town 18 miles from the capital and close to the epicentre of the quake, around 90pc of buildings have been levelled, and residents say they have not received any help yet.
The situation is similar in nearby Petit Goave. "We don't have any aid, nothing at all," one survivor said. "No food, no water, no medical, no doctors."
In Jacmel, a town of 40,000 on the southern coast, residents say they have been forgotten. "What about us?" asked Melanie Piard, who was back in the town from her home in Montreal after a bereavement. "We're stuck here."
And yet for now, even the capital is woefully short of essentials.
"I haven't eaten since Thursday," said Chrisla Aberlam, a 33-year-old woman standing next to the ruined apartment block in Canape Vert. "I lost everything when it fell, except the clothes on my back. My brother lived in there with me, and he is now in hospital. His head was smashed in a very bad way. I don't have money to buy food, so have come back to see if there's anything I can find in the ruins."
Outbreaks of looting and violence are being reported, particularly on the Boulevard Jean-Jacques Dessalines, Haiti's main shopping street, where store owners and policemen fired on crowds attempting to steal basic food supplies and cooking utensils. Two looters were reported dead in the centre of town, while two others were caught by crowds in Del Mar. They were tied together, flogged, and dragged through the streets by rope attached to the back of a truck, before being left in the gutter.
In Petionville, on the south-eastern side of Port-au-Prince, I saw the grizzly aftermath of the lynching of one criminal: a charred body, still smoking, lay by the side of the road. The remains of a tyre were round the corpse's neck. It had been filled with petrol, and set on fire.
His crime? Killing the man who ran the local juice stall, with a revolver. Alerted by the sound of a gunshot, an angry crowd of about 25 men set upon him. "He was a murderer, and the people need to fight fire with fire," said Antoine Miguel, who witnessed the attack.