BOSTON (AP) — Authorities have identified a young girl who was found dead inside a bag on a Boston Harbor beach this summer and whose case sparked a massive social media campaign to find out what happened to her, a law enforcement official briefed on the case said Friday.

Police received information Wednesday that prompted them to search an apartment in Boston’s Mattapan section Thursday, the official told The Associated Press. Authorities have been in contact with some family members of the girl, the official said.

The official was not authorized to release details of the investigation and spoke on condition of anonymity.

A spokesman for the Suffolk district attorney’s office would say only that the investigation remains “very active.” A state police spokesman said in an email that “the investigation is ongoing” but “state police have nothing to add beyond that at this point.” Authorities did not publicly release her identity.

The girl, named Baby Doe by investigators, was estimated to be 4 years old. Her body was found June 25 inside a trash bag on Deer Island in Winthrop by a woman walking a dog.

Police immediately appealed to the public for help in identifying the girl. Using photos of her remains, the National Center for Missing and Exploited Children created a composite image of what the girl might have looked like when she was alive.

Within two weeks of the discovery of her body, the image of the chubby-cheeked, brown-eyed girl had tugged on heartstrings around the world. By early July, the image had been liked on the Massachusetts State Police Facebook page by more than 50,000 people and shared more than 615,000 times, reaching an estimated 47 million people.

Authorities set up an anonymous text line and were flooded with tips. The tips led authorities to check on the well-being of dozens of little girls but did not lead them to Baby Doe’s family.

Despite the widespread publicity, investigators have been frustrated for months trying to figure out who she was and how she died. There were no obvious signs of trauma to her body. An autopsy performed by the state medical examiner’s office did not immediately determine the manner or cause of her death.

Police chased down tips from around the world, but experts determined pollen on the girl’s blanket and leggings and in her hair came from trees found in New England.

Residents of the apartment building that police searched told reporters that investigators asked about a woman who used to live there.

Neighbors said they had not seen a girl who looked like the composite photo released by police since March or April. They said they were told she had been taken into custody of child welfare officials.