A 42-year-old woman died from smoke inhalation due to a fire in a residential building on "Opalchenska" Str. in Sofia, the Ministry of Interior told BTA.
The incident occurred at around 02:20 this night.
A man in unstable mental state was detained for the fire.
Two other children, aged 11 and 13, the woman's husband, aged 48, and an elderly woman, aged 77, were injured.
All of them were taken to medical facilities.
Four fire engines arrived at the scene of the incident, as well as police, who cordoned off the area. The fire has been extinguished.