"Baby Doe," a little girl,whose body was found inside a trash bag on a Boston Harbor island beach about 85 days ago, has finally been identified as Bella Bond.

The mysterious death of the child has engulfed the nation for close to three months. The National Center for Missing & Exploited Children had released a composite of the child, which bears a striking resemblance to images on Rachelle Bond's Facebook page. The composite was shared among approximately 50 million people.

Bella's mother Rachelle Bond, 40, was charged as an accessory to murder, while the mother's boyfriend, Michael McCarthy, 35, was charged with murder, according to Suffolk County District Attorney Daniel Conley, reported CNN.

"At just shy of three years old, Bella Bond was a true innocent. This child, whose very name means beauty, was murdered," said Conley at a news conference, according to BBC News.

"We hoped her death was not a crime but the evidence suggests otherwise," Conley added, reported Fox News.

The child's remains were found in a black trash bag, wearing polka dot pants lying next to a zebra blanket, by a woman walking her dog on June 25. The authorities had believed the child to be between three and four years of age. It has now emerged that Bella was approximately two-and-a-half. 

The authorities have not said how the girl might have died, nor have they talked about any possible motive. No signs of trauma have been found on her body. "That's always a perplexing matter for us. Why does anyone kill a 2-year-old child? What could she have done?" Conley said, according to ABC News.

Boston homicide detectives received "a critical tip" on Thursday, leading to the couple's arrest. While McCarthy is in custody at a Boston-area hospital under treatment for a medical condition, Bond is being held at a separate location.

"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," Massachusetts House Speaker Robert DeLeo said, according to CNN.