news-fire services   It’s believed an early morning fire yesterday at the former Sir James Dunn High School was deliberately set.  Firefighters were called to the Dunn site around 6 yesterday morning and found smoke throughout the halls which made it more difficult in locating which room the fire was coming from.  The fire was extinguished within 45 minutes of arrival of firefighters. One firefighter received minor injuries.  A Sudbury company is currently working on demolishing the facility and trespassers and break-ins have been a problem since demolition got underway.