PHILADELPHIA (WPHL)- Philadelphia fire officials are working to determine what sparked a fire in a Fairmount rowhome that left 12 people dead.

According to the Philadelphia Fire Department, the flames broke out around 6:40 am along the 800 block of North 23rd Street. It took firefighters about an hour to get things under control. According to Philadelphia Fire Department 1st Deputy Commissioner Craig Murphy, once firefighters arrived at the scene flames were shooting through the upper floor windows of the three-story home.

Murphy says a total of 12 people, including nine children, died in the fire. According to investigators, the home was a duplex unit with eight people living in a first-floor unit and 18 living in a unit that occupied both the second and third floors.

According to officials, the home is owned by the Philadelphia Housing Authority. Dept. Commissoner Murphy says during a 2019 inspection, officials installed four smoke detectors. During a 2020 inspection, two addition smoke detectors were installed. Investigators say none of the smoke detectors were working.

In addition to the 12 people killed, officials said eight others were able to evacuate the building. Two were injured, an adult that medics took to Temple University Hospital, and a child that medics transported to the Children’s Hospital of Philadelphia.

The Philadelphia Fire Department is working with the city’s fire marshall office to determine a cause.

Stay with PHL17 for updates on this developing story.