She was 4 years old. She had long brown hair and brown eyes, and she stood about 3½ feet tall. She was dressed in pajamas.
What police don’t know is how she died.
Details about the little girl whose body was found in a plastic bag on a Deer Island beach Thursday began to emerge Friday, as investigators struggled to solve a tragic mystery that has disturbed the area and left residents searching for answers.
“Someone has to know who this child is,” said Robert G. Lowery Jr., vice president of the Missing Children Division at the National Center for Missing and Exploited Children, which is assisting investigators.
An examination by the Office of the Chief Medical Examiner released Friday didn’t establish how a youngster not yet kindergarten age could have died. The child weighed just over 30 pounds, which is average for her height. Her hair was about 14 inches long. The examination did not reveal her ethnicity, according to a statement.
“Neither the cause nor the manner of the girl’s death has yet been determined,” said the statement from Suffolk District Attorney Daniel F. Conley’s office. “Pathologists will undertake additional specialized testing before attempting to make those findings.”
Lowery said forensic artists are preparing a drawing of the girl to be distributed publicly.
So far, she has not been linked to any missing person reports, he said.
“We are still searching, but we can’t find anything,” Lowery said.
Investigators have not determined whether the girl’s body washed up on shore or was left there by someone who accessed Deer Island via land or sea, said David Procopio, a State Police spokesman.
Two State Police divers scoured the rocky coastline Friday afternoon for about two hours near the stretch of beach where the body was found.
“It’s conceivable that additional evidence could be deposited in the ocean, so that’s why we had the dive team go there,” Procopio said. He declined to say what, if any, evidence was found.
The Coast Guard provided investigators with charts of “reverse drifts,” showing where the body might have come from, Coast Guard Petty Officer Cindy Oldham said.
When the Coast Guard is searching for someone who has fallen into the water, Oldham said, they study the tides and currents to determine where that person might have floated. In this case, she said, they did the opposite.
“They went backward instead of forward,” she said. “Looking for where they came from.”
The reverse drifts were calculated to show where a body dropped into the water might have come from after 24 hours adrift, and after 48 hours, Oldham said. But officials are not sure exactly when the body went into the water, she said, so the results were inconclusive.
Deer Island has a wastewater treatment plant operated by the Massachusetts Water Resources Authority and 2.6 miles of paths that are open to the public.
An extensive camera system tracks the plant, but it does not cover the beach where the body was found, said Frederick Laskey, MWRA executive director.
The island includes a public parking lot and road that leads to a guard shack at the treatment plant. Laskey said people staff the plant 24 hours a day and the public road is always open. The MWRA also has security personnel who patrol the island.
The girl was found concealed in a trash bag and she appeared to be wearing pajamas, said a law enforcement official briefed on the investigation. The official, who was not authorized to speak publicly about the case, said a woman found the body while walking her dog, who approached the trash bag on the sand.
The woman noticed the bag was “pretty heavy” and called police, the official said.
Police are searching for the girl’s identity and trying to learn how she ended up on the beach. Investigators also said they do not know how long the girl had been dead when her body was found Thursday about 1 p.m.
Lowery said in cases where a child’s body is found, but no one has reported a youngster missing, caretakers sometimes offer explanations as to why the child is gone to avert suspicion. They may say the child is visiting family or has moved. He urged members of the public to come forward if they hear a similar scenario.
“If the story sounds a little unusual or it doesn’t add up, I really encourage them to contact police,” Lowery said.
While the investigation is concentrated around Boston, he said it is possible that the girl came from elsewhere. He cited the example of a boy who was found dead under a tree in Texas several years ago. The boy, Lowery said, had a severe medical problem and was taken by a relative from the Northeast to Texas.
“It’s heartbreaking,” he said.
The grisly nature of the discovery disturbed many who visited the area Friday.
“I hope they find who did this,” Paul McCluskey said.
McCluskey said he was walking there Thursday when he saw a woman crying near the site where the girl’s body was found. He said he recognized the woman as a Winthrop resident, but did not approach her because she looked like she wanted to be left alone.
Shortly after he saw her, McCluskey said, police officers arrived.
Laskey, of the MWRA, left a pot of yellow chrysanthemums Friday near the site where the girl’s body was found. He said he learned what happened from the Winthrop fire chief, who told him the department was called to the beach because someone had discovered “a baby’s body in a bag.’’
“It’s just unfortunate because it’s such a nice, tranquil place,” Laskey said.
Laskey said he is thankful the child’s body was found and not left in the ocean.
“Despite the tragedy, the horrific circumstances that led to this, [the girl] will have a proper resting place, the poor child,’’ he said.
Evan Allen of the Globe staff contributed to this report. Laura Crimaldi can be reached at email@example.com.