Fire broke out on the second floor of a residence at 710 North Preston Street around 12:30 a.m.
Investigators believe a squatter may have accidentally set the fire while trying to stay warm in the vacant home.
The property suffered heavy damage.
While firefighters were trying to contain the flames, part of the wall connecting the house to another rowhome, collapsed.
Licenses and Inspections evacuated 6 people from a neighboring home.Officials say at least one woman suffered smoke inhalation, but she refused to go to the hospital.