Slaughter of the Innocent

Nassau County Homicide Squad South was summoned to a murder scene on Election Day morning, 2016. An infant girl was found inside a seedy mens room gas station, shrouded with a blood-soaked cotton blanket. The babys throat had been severed with a box cutter, found alongside the body.
Visual examination of the body revealed a deformed right arm and a missing right foot. Crime scene further revealed the presence of a placenta with two umbilical cords. A search of the mens and womens bathrooms failed to yield a second body.
Besides the murdered girl, the only visible clue was a cryptic message, printed in lipstick, posted on the back of the door: Return to sender!