At a press conference Bo Andersson, head of the police for the whole of Örebro County, says they see no political or religious motive behind the suspected crime. "We are working on a broad front and not ruling anything out," he says. They are not worried about any further attacks.
A forensic investigation will be carried out as the suspected crime scene cools off.
Police are asking for members of the public to come forward with any information that may help with the investigation.
The mosque in the Vivalla area is a gathering place for thousands, and is aligned with the Sunni branch of Islam.
Local police officer Fredrik Malm says that for many people in the area it was an important place, and it will leave a big empty space behind it.
The vice-chair of the Islamic cultural association that runs the mosque, Hassan Mountagui, says he is lost for words to thank police and fire services for all they have done. He also says people from the Swedish Church helped during the fire, offering coffee to the people gathered there. "It is a shame when things like this happen. We Muslims are part of Swedish society", he tells Swedish Radio News.
The alarm was raised just after 2am on Tuesday morning. The fire was well underway when the emergency services arrived. So far the southern part of the building has burned to the ground, while the centre is water and smoke damaged and the northern part is largely unscathed.
This mosque survived an arson attack in 2014 when someone threw a suspected molotov cocktail in a window, which failed to catch fire.