Police are still unsure about what caused the blast and are considering the possibilities of a bomb or a gas leak.
Fire officials are still having difficulty assessing the situation because of a risk of the building collapsing. By Thursday morning neither investigators nor dogs had been able to access the site.
Kent Lundqvist, spokesman for the fire department, said, “The work is progressing slowly. We must be extra cautious due to a chance of structural failure. So far we are also unsure of the cause of the explosion.”
Lunkqvist told SvD.se that the blast was so powerful that fire fighters on call at Johannes fire station, around 1.5 km from the apartment, were awoken by the explosion even before the alarm sounded.
No one has yet been reported seriously injured, including the owner, although neither police nor journalists have managed to contact him. It is unclear whether or not he was in the apartment at the time of the blast.
The 48 year old had been held in police custody for about a month on suspicion of stealing books from the Royal Library, where he is an employee. But the prosecutor, Stefan Lind, determined that there were no grounds to continue to hold him and let him go on Friday.
“But we are still keeping him under investigation,” said Lind at the time. The man has confessed to some of the accusations.
The apartment, which is now totally destroyed, had already been searched by police.
“We searched the flat looking for money and books. We found and confiscated remnants of one of the stolen books” said Fredrik Hallström of Stockholm police.
No further searches were planned. Hallström’s reaction to the blast was bemusement.
“We really don’t have any idea what happened. We will continue our investigation. But considering this happened at the same address which we searched, it’s likely to affect our investigation in the end.”
The explosion has significantly affected neighbours and traffic in the area.
“I was in bed sleeping when my outer door suddenly blew into my flat,” recounted Anette Bergvall, a next-door neighbour, to Aftonbladet.
“It filled with smoke and dust, the walls partially collapsed and a pile of debris one metre deep was all that was left of my door.”
Christoffer Sundén lives on Valhallavägen close to the explosion. He was among many who were woken by the blast. “Suddenly I heard a loud bang. It shook the whole city.” he told TT’s reporter.
55 people were evacuated including some 20 who were taken by an SL-bus to a shelter on Kammakargatan.
The entire façade of the building at Surbrunnsgatan 45 is damaged and there is a gaping hole into the fifth floor apartment. The attic above has collapsed into the apartment.
Thursday’s Dagens Nyheter described how Surbrunnsgatan had already become a tourist attraction, with people taking photos with their digital cameras and mobile phones.
“Bloody hell, it’s like Baghdad,” was one comment overheard by the paper’s Eva-Karin Gyllenberg, who was on the scene.
Several blocks surrounding the site, as well as the main thoroughfares of Sveavägen and Odengatan were blocked off, causing traffic chaos for commuters during the early morning rush hour. SL buses were rerouted with long delays.
SL’s spokeswoman, Maria Adolfson said, “We are following police orders.”
Dozens of cars in the vicinity of the apartment were damaged by the pressure wave of the blast and by falling debris.