At just before 5:00 p.m., a family member called 911 reporting a baby in distress.
Emergency service paramedics arrived and transported the baby girl to Sacred Heart Hospital where the child later died.
A neighbor says he saw the child's father standing outside with a bible crying shortly before Allentown police took him and the child's mother in for questioning.
A woman later arrived on the scene to find out what was going on and shortly thereafter emerged screaming that that was her grandchild.
Neighbors say the family only recently moved there to a second floor apartment and nobody really knew them.
Police are saying very little.
"We're conducting an investigation now into exactly what occurred…we really can't comment more on what's going on, but we are conducting an investigation into what exactly took place," Allentown Police Captain Dean Schwartz said.
Police continued to question family members late Thursday.
Officials expect to hear from the coroner Friday on the cause of death.