An investigation into a fire at a Chicago apartment building where 10 children died could not determine whether it was accidental or deliberate.

The Chicago Tribune reports fire officials said Friday that the Aug. 26 blaze was started by a person but that doesn't necessarily mean arson. The investigation found the fire was started by an open flame in an enclosed rear porch.

The nine first cousins and close family friend whose ages ranged from three months to 16 years old were having a sleepover in the apartment building when the fire broke out. There were no survivors.

After the fire, city officials issued more than 40 code violations against the building's owner.

The building in the Little Village neighborhood is scheduled to be demolished in July.