Following a nine-day inquiry, the Board of Police and Fire Commissioners reported that they were unable to determine the cause of the 1871 Chicago fire. The board questioned 50 people and amassed more than 1,000 pages of testimony.
The official report states that whether the fire originated from a spark blown from a chimney on that windy night, or it was set on fire by a human, they were unable to determine the cause. As the fire burned, The Chicago Evening Journal reported that it started when a cow kicked over a lamp while a Mrs. O'Leary was milking. Regardless of the findings of the board, Catherine O'Leary endured inescapable blame that led to the light-hearted folksong, “There'll Be A Hot Time In The Old Town Tonight!"