Neighbors said that the house where the child was left belongs to a lawyer, and that his son may have been the one to find the baby.
Lenora Alston, 50, a Marvine Street resident, said she saw police at the house Saturday morning and walked over to find out what was going on.
When she got to the scene, she saw a cop who had blood on the front of his shirt. The baby, she said, was covered up by the blanket left with her, and an ambulance was parked in front of the house.
"You know well enough when an ambulance don't move, someone didn't make it," Alston said.
She hypothesized that the mother could have been one of the "smoker girls," or crack addicts, who hang around the neighborhood.
"The only thing I could think of is that the girl couldn't make it no further," Alston said. "But to have a baby and just leave it, that's cruel."
Police don't know why the baby was left on the porch, but neighbors speculated it was because the homeowner's porch light never worked.
However, by yesterday afternoon, a fluorescent bulb was burning brightly on the front porch in broad daylight. No occupant came forward when a reporter knocked on the door.
Francine Long, 59, who has lived on the block for 30 years, said that if a nearby streetlight that's been out since Hurricane Irene had been working, the mother might not have abandoned her baby there.
"That could have been a deterrent," Long said. "It's terrible. Just terrible."
As of last night, police were awaiting autopsy results to determine the cause of the baby's death. They also were still searching for the mother, who may need medical assistance.
The mother could have left her baby at any hospital with no questions asked, under Pennsylvania's Safe Haven law, which allows parents to leave babies up to 28 days old at any hospital without legal consequences.