The cause of the fire in an apartment in an apartment building in Garbsen near Hanover has not yet been clarified.
The police said on Monday that it was being determined whether there was a technical defect in the bedside of the 71-year-old resident.
The investigators also found cigarette remains on the bedside and are now investigating whether the fire could have been kindled by a smoldering cigarette.
Garbsen - The wife of the same age of the deceased suffered life-threatening injuries and is still in mortal danger, as it was said.
The house was badly damaged by the fire on Friday and is no longer habitable, the damage is estimated at around 800,000 euros.
dpa
