The information comes as police have begun a technical examination of the burned-down houses - until now it has been too hot for forensic experts to work at the site.
The police tell VG that they have a hunch about where the fire started but do not yet know the cause.
One person is suspected of causing the fire, although police emphasize that the person is not yet suspected of any crime. Police questioned the suspect on Wednesday and the person is described as "cooperative."
"Right now there is not enough information to say whether the person will be charged with a crime," police representative Nina Fladhus tells VG.
Instead, the police are working with several hypotheses, one of which is that the person started the fire through negligence, another is that something spontaneously combusted.
The fire, considered the largest of its kind in over 100 years, broke out on Friday and quickly burned more than 100 homes to the ground. More than 400 people were evacuated from their homes.
