It was the night of January 10 that a villa in a village outside Gällivare caught fire and a woman suffered serious burns.
A man in his 80s was arrested and is suspected of arson and attempted murder after the incident.
However, Moa Grahn, prosecutor who leads the murder investigation, confirms to Norr Media that the woman has died and that she will request that the suspected act be reclassified as murder.
They plan to hold new interrogations with the man.
The man is being held because the prosecutor believes there is a risk that the suspect will hinder the investigation at large.