Accident or arson? The Hartford Circus Fire and the unidentified does

In 1944 a fire at the Ringling Bros and Barnum and Bailey circus in Hartford, Connecticut led to the deaths of 168 people, of which 5/6 people still remain unidentified. As well as finding these identities, investigators have battled for decades to find the true cause of the fire - was it a carelessly discarded cigarette or something more nefarious?