According to investigators, the incidents appear to be gang-related.
The Pennsylvania State Police said the Thursday fire started when someone threw a firebomb known as a 'molotov cocktail' onto the porch of one of the homes.
The blaze broke out about 1:20 a.m. in a house on the 1000 block of Stanbridge Street.
Terrified neighbors awoke to choking smoke and raging flames. Residents of nine homes fled into the night.
"When I woke up I smelled the smoke like something was on fire," said fire victim Mirna Marchese.
"The next thing you know the policeman is banging on the door saying 'you got to get out,'" said fire victim Joseph Cerminara.
Sandy Orth's parents live next to the house that was firebombed. Her 79-year-old mother, Mary Bibbo, remains in a medically induced coma at the hospital suffering from smoke inhalation. Her father was treated for minor injuries.
"My father was sleeping on the chair in the living room and the cops were banging on the door and he saw a big burst of flame come through. He tried to get upstairs to rescue my mother but it was too smoky. One of the firemen ran upstairs and got her out through the window," Orth said.
It took almost an hour to get the fire under control. Four of the houses on the block are left uninhabitable. Five others suffered heavy smoke damage.
Investigators say this firebombing is connected to another that happened Tuesday night at a house five blocks away. The people who live there are relatives of last night's intended victims.
Sources tell Action News that a young woman who lives in the house that was firebombed last night has been dating a gang member.
Her cousin's house was targeted Tuesday and now her house.
Investigators are trying to figure out exactly what caused the eruption of violence, and who is responsible.