Fire Commissioner Lloyd Ayers made that annoucement in a news release on Tuesday afternoon.
Rahseeda Wilson and her family died in the blaze on Thursday in the Feltonville section of the city.
The fire broke out around 1:30 a.m. in the 4800 block of North Palethorpe Street.
Her 8-year-old dauaghter Shanai, 11-year-old daughter Minyan and 14-year-old son Jamar were also killed.
Firefighters arrived four minutes after the alarm went out, finding thick smoke and heavy flames pouring out of both floors of the house.
Neighbors said they tried calling Wilson on her cell phone, but the only sound from the other end was the frantic pushing of buttons.
Rasheeda's body was found in the front bedroom, while Jamar was found in a middle room. Minyan and Shani were found in a rear bedroom.
Investigators have found only one smoke alarm in the basement and did not have a battery.
Neighbors say Wilson was well liked, was a block captain and was very active in her church.
Neighbors on either side were also burned out in the blaze.