http://abcnews.go.com/US/wireStory?id=3269857 By RAMESH SANTANAM The Associated Press PITTSBURGH Fire raced through a three-story row house early Tuesday, killing five children, and authorities said they were looking for a teenage baby sitter who was supposed to be watching them. Neighbor Sontaya Perry, 22, said she could hear the children inside the house screaming as the fire raged from the windows before dawn. She said she tried to get in, but the wooden steps leading to the door were in flames. "They were screaming, and five minutes later they stopped screaming," Perry said. On the street outside, two boys were begging for someone to help for their brothers and sisters, she said. The victims, ages 3 to 7, were all found on the second floor, authorities said. One was dead on arrival at West Penn Hospital and two others died in the emergency room, said Stephanie Waite, a hospital spokeswoman. The Allegheny County Medical Examiner's office said it had the bodies of a boy and a girl. Two other children were able to escape without injury. Police said a teenage baby sitter was supposed to be watching the children, from two different families, while their parents were out for the night. A police statement said three of the five children who died lived in the house and the two others lived elsewhere, but it did not clarify their relationships. The baby sitter had not been located as of late morning and police only knew her nickname, which they didn't disclose, Police Chief Nate Harper said. "We have a lot of people out there working hard. ... Hopefully we'll have answers in a short period of time," he said. Tuesday morning, investigators were inside the gutted and blackened house skeleton of the home, examining what remained and trying to determine the cause of the fire, which officials believe started on the home's second floor. Officials said flames had been shooting from all three floors of the building in the city's East Liberty section when firefighters arrived around 1:20 a.m. The blaze also damaged a vacant building next door. Associated Press writer Daniel Lovering in Pittsburgh contributed to this report.