As he walked up the steps from Stockholm Central metro station, surgeon Guglielmo Rufolo di Ravello noticed people flooding towards him, screaming.
Then he saw the truck.
As he watched, it began to move "really fast, that scared everyone ... people ran inside of stores ... taking refuge," he says.
Looking around, Rufolo di Ravello spotted two young children, aged about 7. They appeared to be alone, and he knew if he didn't act, they might get hurt.
"As a doctor," he says, "I am used to being in situations where I can provide assistance."
Instinctively, he pulled the children out of harm's way, and hurried them to safety. Two women joined them as they moved. "I try to provide help, to take them with me," he recalls, 24 hours after a truck became a deadly weapon.
Scene of carnage
Drottninggatan (Queen Street) is a bustling commercial district in the heart of Stockholm. It's a popular destination for tourists looking for souvenirs, and for locals meeting for a meal or shopping in one of the big-name stores that line the narrow, car-free thoroughfare.
But on Friday afternoon, it was the scene of carnage, when that truck plowed into pedestrians, killing four
and leaving more than a dozen injured.
The truck was hijacked while making a delivery nearby, shortly before the rampage. A 39-year-old man from Uzbekistan has been arrested
on suspicion of terrorism offences.
Rebecka Mohell was with her friend Juan in a cafe just around the corner from where the truck was snatched. It raced past so fast that chairs were flung into the air, hitting two young women who had been sitting outside.
Mohell, 34, admits she's still reeling from Friday's events. Clutching a cup of tea with both hands, she says she's been on "an emotional roller coaster" ever since.
"I heard this swoosh -- I don't know what happened," she remembers. "It went by so fast, I just saw the dust. Then these girls came in screaming and crying.
"I was standing there panicking ... then there was this tiny brief moment where I was like 'we could actually die' and I just grabbed Juan." She says she was shaking as she realized, "I just need to get to safety."
Kristoffer Rengfors works in a fourth-floor office overlooking the truck's path. He was alerted to the unfolding disaster in the street below by the screams of people in his team.
"Panic broke out. People were screaming, 'That was a truck, that was a truck, it came down the street!'" he says. "We realized pretty fast that this is not some drunk driver who has missed the turn. This is something else. You don't drive a truck down the street like that if you've fallen asleep."
He says the vehicle accelerated as it passed his building, which is just meters from the site of a failed terror attack in 2010
, when a man targeting Christmas shoppers died when his explosives detonated prematurely.
"My colleagues panicked, people broke down, some had to go and throw up. We had complete chaos at the office," he says, adding that his first instinct was to try and get people away from the windows, fearing what might happen next.
Some went out onto the balcony "to look," he says "and [saw] the things ... nobody should see. [Afterwards,] they said, 'Why did I go out there, why did I look?'"
Lockdown in place
With the city center in lockdown, shoppers and workers were trapped wherever they happened to be, unable to leave stores, offices and restaurants, as police swarmed the streets and a manhunt began.
Eva Elestrom, 60, and her daughter Isabelle, 23, from Uddevalla on Sweden's west coast, had just arrived in Stockholm and were checking in to their hotel when the sound of sirens echoed across the lobby.
"Then we heard that we couldn't leave, and they wouldn't let anyone out or in," says Isabelle. "They just closed the hotel ... because they didn't know if there was anything more."
"They closed everything," Eva adds. "Nothing was open, no theaters, no cinemas, everything was just locked down."
Mohell says eventually the cafe she was in closed too, and she and her friend had to head out onto the street, where they came face-to-face with chaos.
"We made our way past the ambulance and two injured girls who lay strewn on the street," she says, adding: "I could see all the blood. Someone else told me he saw body parts scattered over the street. It was just awful."
She says this is when Juan took control, leading her through alleys and smaller streets to get away from the area and onto a bus home.
"I just thought I'll keep it together now and I'll let all [the fear] out when I get home, and that's what happened," she recalls. "When I was still in the city I saw people crying but the further out I got, it was like people weren't really affected by it. I felt so alone."
Makeshift memorials at scene
Stockholm's residents emerged defiant on Saturday. Ahlens City department store was still closed off; debris still littering the sidewalk as police and security forces continued their investigation.
But outside the Stockholm Concert House, stalls were being set up at a farmers' market, and flower sellers were soon doing a brisk trade. Many customers carried their freshly-bought blooms straight to the cordon and laid them down in quiet tributes.
A man walked determinedly around the corner, clutching a bouquet of delicate white and pink roses, but appeared to falter, overcome with emotion, as he approached the makeshift shrine. One of the heavily-armed officers standing guard sprang into action, stepping in to offer words of comfort.
Harib Jlassi, 29, a night bus driver from Stockholm had brought his three-year-old daughter with him, to offer prayers and blessings for those killed and injured. "I've come to show that we are not afraid," he says, his eyes red and face puffy from crying. "We are not scared. We are stronger than them."
Memorials have sprung up at every cordon. Roadworks had been underway outside the store along Klarabergsgaten before the attack, now mourners use the temporary fencing erected around them as a trellis, creating a wall of flowers.
Musician and singer Sun Erkensten, 58, says she had been due to meet a friend in the city center yesterday afternoon, but changed her plans at the last minute.
"It's important to come here [to the memorial] because I have to take back my streets in my mind," she says, her voice barely rising above a whisper. "I have to be brave enough to mourn. It's going to take time. The shock is still here. Slowly you forget things. That's when the real work starts."
Return to normality?
Terrorism analyst Magnus Ranstorp, from the Swedish National Defense College says Swedes will likely see a noticeable police presence on the streets "for some time, for reassurance," but it's not clear if there will be long-term security changes as a result of Friday's attack.
"In 2010, we had this failed suicide bomber and that did not jolt anyone into any reaction," he explains.
Ransdorp says that while heavily-loaded vehicles can make "formidable killing machines," it isn't practical to ban them from city centers: "Every day, trucks have to get in to deliver goods."
Rengfors is adamant that life in Stockholm must return to normal as soon as possible.
"These people want you to be scared," he says. "If you don't go to work, then they win. I'm not going to let that happen. So I'm going to go to work on Monday, and I hope other people will as well."
"Life has to go on," he adds. "I didn't feel unsafe before this, and I don't feel unsafe now."
Eva Elestrom says she thinks the attack "will make people closer to each other," but worries it will also force her to be "more careful not to be in open places ... more vigilant." But, she says, "We decided this morning that we are going to get out, do some shopping ... This is not going to destroy our weekend."
Mohell, too, is determined not to give in to the terrorists responsible for this and other attacks like it.
"The scary part, I think, is Sweden is supposed to be so safe -- if it can happen here, it can happen anywhere."
But, she insists, "We can't let fear overtake us. Fear feeds hatred."