Arson investigators are trying to figure out the cause of a deadly house fire on the city's South Side on Saturday night. San Antonio fire crews responded about 10:15 p.m. to the fire on Flanders Avenue near Packard Street. After they brought the fire under control, firefighters found a person dead inside the home. There were no other injuries reported. Firefighters say the fire heavily damaged the home, and estimated the damage at $80,000.