Suffolk District Attorney Dan Conley said during a Thursday press conference that an autopsy was performed on the girl, who was found on the Winthrop island on June 25.
“Who she is remains a mystery to us,” said Conley.
Police have received dozens of tips since the girl’s body was found, but none have helped determine who she is.
John Schettino of Ariana’s Coffee Shop says “It just hits your heart when you see a little child in such a bad situation.”
He posted a flyer of the unidentified girl to his store’s windows in the hopes someone will recognize her.
Susan Brazil, who works at the MWRA office near where the girl’s body was found, says the office was devastated at the news.
The girl is believed to have been about four years old at the time of her death.
She is described has about 3.5 feet tall, weighed about 30 pounds and had brown eyes and brown hair.
Investigators released a composite image of the girl created by the National Center for Missing and Exploited Children.
In addition, investigators released pictures of a pair of leggings and a zebra blanket that were found inside the trash bag where the girl was found.
Conley said it does not appear the girl had been on the beach for very long.
Anyone with information is asked to call the Suffolk County State Police Detective Unit at (617) 727-8817, Massachusetts State Police at (508) 820-2121 or Winthrop Police at (617) 539-5806.
Watch: District Attorney Dan Conley on Deer Island Investigation