STOCKHOLM: The suspected Stockholm truck attacker had shown interest in extremist groups and was facing deportation after being refused residency, Swedish police said on Sunday.
A second suspect has meanwhile been formally placed under arrest in connection with the attack that killed four people and injured 15 others, the Stockholm district court said on Sunday.
The news came as thousands of people gathered under sunny spring skies amid a sea of flowers and candles to honour the dead and to stand against terrorism.
The first suspect, identified only as a 39-year-old man from Uzbekistan who was arrested hours after Friday's attack, is suspected of having sped a stolen beer truck several hundred metres (yards) down the bustling pedestrian street Drottninggatan in the heart of Stockholm.
The vehicle mowed down shoppers before slamming into the facade of the busy Ahlens department store.
The motive for the attack was not known, but the method resembled previous attacks using vehicles in Nice, Berlin and London, all of them claimed by the Islamic State (IS) group.
There has been no immediate claim of responsibility for the Stockholm attack -- the third in Europe in two weeks, after a car and knife assault outside London's parliament and the Saint Petersburg metro bombing.
The 39-year-old suspect in the Stockholm attack "showed interest for extremist organisations like IS," police chief Jonas Hysing told reporters.
The suspect had also been due to be expelled from Sweden after his residency application was rejected last year.
"He applied for a permanent residency permit in 2014. The Migration Agency rejected it in June 2016 and also decided that he was to be expelled," Hysing said.
"In December 2016, he was informed by the Migration Agency that he had four weeks to leave the country. In February 2017, the case was handed over to the police to carry out the order, since the person had gone underground," he said.
But police apparently never found the man, whom authorities have said was known to Sweden's intelligence service for undisclosed reasons.
- 'Lovefest' vigil -
Swedish Prosecution Authority spokeswoman Karin Rosander said meanwhile that the second suspect was arrested "on suspicion of a terrorist crime (by committing) murder", the same accusation as against the first suspect.
No other details about the person were disclosed.
The family of an 11-year-old Swedish girl have meanwhile confirmed she was one of the four people killed in the attack.
The Foreign Office in London said Swedish police had confirmed to them that a British man was among the dead, while the Belgian foreign ministry said a Belgian woman had been killed.
The fourth victim was only known to be a Swedish national. Fifteen people were injured, four of whom were in critical condition.
Police had said on Saturday they were increasingly sure the 39-year-old was the driver of the truck.
"There is nothing to indicate that we've got the wrong man. On the contrary, the suspicions have strengthened," Swedish police chief Dan Eliasson said.
Police had found a suspect device in the cab of the truck.
"A technical examination is ongoing, we can't go into what it is right now... whether it's a bomb or a flammable device," Eliasson said.
Sweden has been trying to get back on its feet after what authorities have termed a terror attack.
Thousands of people gathered on Sunday for a "Lovefest" vigil against terrorism and to honour the victims at the Sergels Torg plaza near the scene of the attack, where a sea of flowers, candles and stuffed toys had been placed by mourning Swedes.
Friday's attack has deeply shocked the usually tranquil Scandinavian nation, which prides itself on its openness and tolerance.
It was the second terror attack in Stockholm.
In December 2010, a suicide bomber blew himself up, also on the Drottninggatan street, slightly injuring several passersby.