Glenwood authorities said firefighters were called to the 900-block of East 194th Street around 5 p.m.
The fire had fully engulfed a condo on the second floor of a three-story building when firefighters arrived, officials said.
Officials said one person has died, and the investigation is active.
Neighbors in adjoining condos in the building were displaced, and officials contacted the Red Cross for assistance.
Officials said they expect to release more information on Sunday.