“The threat level has not been raised, but after what happened, we think Stockholm residents need to see more police around town, to talk to us about this very serious event that has taken place,” Stockholm police spokesman Kjell Lindgren told AFP.
Uniformed police officers and civilian volunteers wearing fluorescent yellow police vests patrolled the streets, subway and train stations and shopping centres.
“We want to be wherever there are a lot of people…to make our presence felt,” Lindgren said.
A man strongly believed to have been Taimour Abdulwahab, a native of Tranås three hours southwest of Stockholm, was the only person to die on Saturday when he carried out the first-ever suicide bombing in Sweden.
He was carrying a cocktail of explosives which is believed to have detonated prematurely near a crowded pedestrian street before he managed to kill “as many people as possible,” prosecutor Tomas Lindstrand said Monday.
Two other people were injured when his car exploded nearby minutes earlier.
“We are turning every stone in this case,” deputy chief prosecutor Agnetha Hilding Qvarnström — who took over the probe Tuesday — told AFP, refusing to provide more details on where police were searching for possible accomplices.
“We are casting a very broad net now at the beginning of the investigation,” she said.
Sweden’s intelligence agency Säpo said it had launched “a broad international cooperation” with authorities “in the other Nordic countries, the rest of Europe and of course in the United States.”
“We are looking into different kinds of leads,” Saepo spokeswoman Sofia Oliv told AFP, without giving details.
Oliv refused to comment on work mapping Islamic extremists within Sweden, but according to the Aftonbladet daily, a report from the intelligence agency shows it knows of around 200 such people living in the Scandinavian country.
Up to 80 percent of them are part of so-called “violence-prone networks,” while the remainder are “loners” and people with extremist contacts abroad, according to Aftonbladet’s summary of the report, to be published Wednesday.
Aftonbladet also quoted Säpo’s head of security as saying the investigation so far showed the alleged bomber had no links to any known extremist groups.
Säpo spokeswoman Anna Maria Böök stressed that while no links had been found up to now, the investigation was continuing.
Seven bomb experts from the US Federal Bureau of Investigation were coming to Sweden to help with the probe conducted in cooperation with British police. Abdulwahab lived in the town of Luton, near London, with his wife and three children.
The far-right, anti-immigrant Sweden Democrats said Tuesday the attack showed the need for a public discussion about Islamist extremism.
“People want to know how we as politicians look at Islamic extremism and what the preventive work looks like,” party leader Jimmie Åkesson said, demanding a parliamentary discussion before Christmas.
However, the other parties in Sweden’s parliament, the Riksdag, rejected the idea, worrying such a debate would fuel xenophobia.
The attack profoundly shocked Swedes, with Foreign Minister Carl Bildt telling the BBC the bomber appeared to have been intent on causing “mass casualties of a sort that we have not seen in Europe for quite some time.”
The episode also prompted soul-searching in Britain after it emerged that Abdulwahab had a reputation for his extremist views.
The chairman of a mosque in Luton where he used to worship said he had stormed out in 2007 after being confronted over his support for jihad.
An Islamist website, Shumukh al-Islam, posted a purported will by Abdulwahab in which said he was fulfilling a threat by Al-Qaeda in Iraq to attack Sweden.