The 39-year-old man from Uzbekistan drove a 300-tonne truck into bystanders on Queen’s Street on Friday, killing four and injuring 15.
But bystanders said that he was mainly targetting children, and sent prams “flying into the air” as his vehicle zigzagged along the street.
Glen Foran, an Australian tourist saw the moment the truck hit a pram.
He said: “I turned around and saw a big truck coming towards me. It swerved from side to side. It didn't look out of control, it was trying to hit people.”
“It hit people, it was terrible. It hit a pram with a kid in it.”
Rakhmat Akilov appeared to target children during his murderous rampage
Mr Foran said it “felt like forever” waiting for police to arrive on Drottninggatan in central Stockholm, where the man had hijacked a beer delivery truck and hurtled down a busy shopping street before crashing into a store and catching fire.
He said: “It took a long time for police to get here. I suppose from their view it was quick, but it felt like forever.”
Hours after the attack, police released a CCTV image of the suspect on an escalator wearing a grey hoodie and carrying a blue mobile phone.
Onlookers said that the terrorist deliberately drove into the path of innocent children
He was arrested several hours later in Marsta and police revealed more information about him on Sunday.
Sources have named him as Rakhmat Akilov and it has been claimed the suspect had expressed sympathy for Islamic State.
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He was also wanted for failing to comply with a deportation order, Swedish police said on Sunday.
Police said that two of those killed were Swedes, one was a British citizen, and one was a Belgian.
Rakhmat Akilov has been named as the suspect who carried out the truck attack
The Briton was named as Chrispin Bevington, a dad-of-two, the other dead was a female Belgian tourist, 31, and two Swedes including an 11-year-old girl who was walking home from school.
Police said that all have been identified and their relatives informed.
The attack echoes those carried out in Nice, Berlin and London when people used vehicles as deadly weapons.
Those attacks were claimed by Islamic State, but there has been no such claim yet for the Stockholm assault.
A Briton killed in the attack was named as Chrispin Bevington on Sunday
The Uzbek man remains in custody and must appear before a judge before midday on Wednesday.
Sweden's prosecution authority said a second person had been arrested on suspicion of having committed a terrorist offence through murder, but police said they were more convinced than ever that the Uzbek man was the driver of the truck.
Another five people were being held for questioning after raids and police said they had conducted about 500 interviews.
Although nine of the 15 people injured remained in hospital, two in intensive care, Stockholm began to return normal on Sunday with the removal of police barricades along the Drottninggatan street where the attack took place.
The Stockholm Terror attack – in pictures
Fri, April 7, 2017
The vehicle drove into crowds on Drottninggatan (Queen Street) – one of the city's major pedestrian streets, just before 3pm local time, before crashing into Åhlens Mall
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Truck rams into crowds in central Stockholm
On Sunday, three days after his attack, thousands gathered in the spring sunshine near the site of his crime for a vigil.
They met to show their support for those killed or injured.
Hundreds of flower bouquets covered steps leading down to the square next to where the truck ploughed into the Ahlens department store, with more piled up under boarded-up windows.
Only yards from the scene, thousands of people gathered in the Sergels Torg square in a show of unity as heavily armed police stood guard and a police helicopter hovered overhead.
Eva Udd, a 55-year-old nurse who had joined the demonstration with a friend, said: "I want to show I'm not afraid to go out. I usually never go to things like this, but this just felt so very important."
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