'A deal with the devil': Will jury believe Bella Bond's mother?

BOSTON — A Boston jury is expected to hear the opening statements Tuesday in the murder trial of the man accused of killing 2-year-old Bella Bond.

Her body washed up on Deer Island two years ago. And for months, she was known only as "Baby Doe."

A group of 16 jurors have been picked to hear the case in Suffolk County Superior Court and the case hinges on the testimony of one person -- Bella's own mother.

"The Suffolk County DA's office has made a deal with the devil," former federal prosecutor Brad Bailey told Boston 25.

Rachelle Bond has already pleaded guilty and admitted she helped place the body of her 2-year-old daughter in a bag, which was dumped in Boston Harbor.

But Bond claims her ex-boyfriend, Michael McCarthy beat Bella to death in her Dorchester home.

Bailey says the jury will have to decide if they believe Rachelle Bond, or if they think she's lying to stay out of jail.

MORE: Trial for man accused of killing Bella Bond to begin Monday

“If you take into account everything else and then you know what she is getting, then you know how much that may be motivating her,” Bailey said.

In return for her testimony against McCarthy, bond is expected to receive a sentence of time served, plus two years of probation.

“She was being controlled by Michael McCarthy, she really loved her daughter,” Bond’s attorney, Janice Bassil, argued.

In court, Rachelle Bond is expected tell the jury why she never reported her daughter's death to police and why she allegedly helped McCarthy cover up the crime. She is expected to say he beat her up and also beat up a local drug dealer while she watched.

Legal experts say this will be a case of "he said, she said."

"Obviously, neither one of them comes across as particularly responsible. But the jury really has a tough decision to decide who is telling the truth here," criminal defense attorney Peter Elikann told Boston 25.

McCarthy is charged with first-degree murder. If convicted, he faces a mandatory sentence of life in prison without parole.

>> Remains of toddler found in trash bag on Deer Island

>>Remember Me? New billboard hopes to remind public of 'Baby Doe'

>>'Baby Doe' identified, mother and mother's boyfriend arrested

>>Report: DCF did not properly assess risk at Bond home

>>Mother of Bella Bond to testify against boyfriend in murder trial

>>Timeline: The 'Baby Doe' investigation from the beginning

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