Karen:

The Great Boston Fire of 1872

Episode sources:

1. Damrell's Fire, documentary by Bruce Twickler

2. Damrell's Fire Lecture

3. The Story of the Great Fire: Boston, November 9-10, 1872 by Carleton Coffin Charles

4. Great Boston Fire of 1872 Wikipedia

Georgia:

The murder of Mary-Lou Arruda

Episode sources:

1. Historical Crime Case Study: Footwear, Tire and Tool Mark Impressions

2. Mary-Lou Arruda Find A Grave

3. RaynhamPD.com article by Benjamin Paulin

4. WCVB.com article by Charlie Peters, The Enterprise