The Baby Doe mystery has been finally solved by Boston police.

The 3-year-old girl was identified as was Bella Amoroso Bond, Suffolk County District Attorney Daniel Conley said on September 18.

Baby Doe, also known as Deer Island Jane Doe, was found dead in a plastic bag on the shore of Deer Island in Boston, but remained unidentified despite months of appeals from investigators.

Police commissioned a computer-generated image of the girl to help identify her and the picture was shared millions of times online.

The girl’s body was found by a woman walking her dog on June 25.

Boston police said on September 18 they have spoken to members of the girl’s family.

Photo Boston Police Department

On September 18, Bella’s mother, Rachelle Bond, 40, was charged as an accessory to murder after the fact, Daniel Conley told reporters.

Rachelle Bond’s boyfriend, Michael McCarthy, 35, was charged with murder, according to Daniel Conley.

Michael McCarthy is not Bella’s biological father, according to a law enforcement source.

The couple will be arraigned on September 21. Neither of them, or lawyers representing them, had commented on the case as of September 18.

“This child, whose very name means beauty, was murdered,” Daniel Conley said.

Massachusetts House Speaker Robert DeLeo told reporters that Rachelle Bond and Michael McCarthy blamed each other for the death.

“It appears as though it was a situation of a boyfriend who was involved and that apparently, I think, mother and boyfriend sort of blaming each other in terms of who harmed the child.”

Meanwhile, investigators also searched a home in the city. Police did not disclose additional information, saying the investigation was “very active”.

The case received a massive response on social media and drew thousands of new visitors to government websites.

Police received hundreds of tips from the public, but they were unable to find anyone who knew the girl until now.

Investigators still have not determined how she died because there were no signs of trauma found on her body.