DEER ISLAND — The remains of a girl believed to be a toddler were found on the shoreline of Deer Island on Thursday afternoon by a woman walking her dog, a chilling discovery that stunned neighbors and prompted police to call for the public’s help in identifying the child.
During a news conference at the scene, State Police Lieutenant Colonel Frank Matthews said the woman found the remains around 1 p.m. Matthews and Suffolk Assistant District Attorney Mark Lee provided no other details, including the length of time that her remains were on the shoreline and whether there were signs of foul play.
A law enforcement official with knowledge of the investigation said the remains were found in a plastic trash bag. Another law enforcement official briefed on the case said authorities believe the child’s remains may have washed up on the shore.
The Office of the Chief Medical Examiner will conduct an autopsy Friday, officials said.
One neighbor, Candis Gillette, said she was walking her dog near Taft Avenue when she came upon the woman who had found the girl’s remains and she saw a plastic bag.
“All of a sudden, police cruisers pulled in and they were talking to a woman,” Gillette said. “She looked visibly upset and I could see she was crying.’’
Gillette called the discovery “tragic.”
“I just hope they find whoever did this,” she said.
Like other neighbors, she called for a heavier security presence in the public park on Deer Island, which is also home to a large sewage treatment plant. She said the entrance to Deer Island has no gate and young people frequently gather there for parties and drinking. Gillette said she has found syringes there.
Matthews said during the briefing that investigators will seek help from the National Center for Missing and Exploited Children in identifying the girl. Appealing to the public, Matthews said, “if anyone knows about a child that might be missing . . . please reach out to us.”
He said investigators have “plenty of officers that are looking into” security protocols on Deer Island and whether there are any surveillance cameras in the area.
Ria Convery, a spokeswoman for the Massachusetts Water Resources Authority, which operates the sewage treatment plant on Deer Island, said cameras are focused on the main part of the plant, but not in the public access area. Security guards are on duty at all times and conduct “regular rounds around the whole island,” Convery said.
Police in nearby communities, including Winthrop, Nahant, Revere, Boston, Saugus, Chelsea, and Lynn, either could not be reached for comment or said they had no missing persons reports for toddlers.
Deer Island connects to the town of Winthrop. In addition to State Police, Winthrop police and the Coast Guard are investigating. District Attorney Daniel F. Conley’s office said in a statement that the Coast Guard is helping to analyze “drift pattern of the waterways around Deer Island.”
Police canine units arrived on the island shortly after 6 p.m. to help with the investigation.
Another neighbor, Kenny Bliton, said this is a close-knit community, but summer can be a raucous time.
“In the winter it’s quiet, but during the summer, it’s ridiculous,” Bliton said. “There’s no patrol. No park rangers.”
Tina Anzuoni, a longtime resident of Tafts Avenue next to the island, said the shore is supposed to be closed to visitors at dusk, but it is unsupervised.
Her concerns were echoed by Mike Herbert, who lives near Anzuoni.
“Since they made it a park, it’s been hectic,” Herbert said. “People outside at all hours.”
Convery said disturbances sometimes occur, as with any open space, but such incidents “are “infrequent and [have] not been a big problem.”
Matthews said at the briefing that he could not report any additional witnesses besides the woman who discovered the remains.
Anyone with information about the case is urged to call the Suffolk County State Police Detective Unit at 617-727-8817 or the Winthrop police at 617-539-5806.Globe correspondents Aneri Pattani, M.G. Lee, and Matthew MacCormack contributed to this report. Astead W. Herndon can be reached at astead.herndon
@globe.com. Travis Andersen can be reached at firstname.lastname@example.org Follow him on Twitter@TAGlobe.