Indianapolis firefighters responded to another suspicious house fire near downtown Indianapolis on Wednesday morning, a day after the city was struck by 10 other fires, including seven confirmed as arson. Wednesday morning’s blaze heavily damaged a vacant home in the Fountain Square area about 6:35 a.m. Investigators suspect arson. Officials say they believe at least three of Tuesday’s fires were set by the same person. Police say they have identified at least two "persons of interest." A woman was killed and her son critically injured in one of the fires.