BOSTON — The trial began on Monday for a Massachusetts woman accused of killing her pregnant friend, cutting the fetus out of her body and later attempting to pass off the baby as her own.

Julie Corey, 39, was arrested in 2009 for the murder of Darlene Haynes and the kidnapping of her unborn child, who survived and is living with her biological father.

Assistant District Attorney Dan Bennett said during opening statements in Worcester Supreme Court on Monday that evidence would prove Corey faked her own pregnancy and then cut out Haynes' unborn baby, after beating and strangling Haynes to death in the apartment that they shared, according to local press reports.

Rick Cinclair / Worcester Telegram & Gazette via AP Defendant Julie Corey, 39, sits in Worcester, Mass. Superior Court on Monday, Jan. 27, 2014 as she waits for her murder trial to begin.

"Her intention was to take the baby away from Darlene Haynes," Bennett was quoted as saying by The Boston Globe.

Haynes, 23, was eight months' pregnant at the time.

Prosecutors have said that Corey told her boyfriend the baby was theirs and then convinced him to move with her to New Hampshire where she was arrested, days after Haynes' body was found by her landlord. The boyfriend was never charged.

But Corey's attorney, Michael Wilcox, said police had botched the investigation, lost evidence and failed to find a murder weapon, according to the press reports. He argued Corey had not killed Haynes and had obtained the baby by legal means.

Corey, who pleaded not guilty to the charges, has been in prison since her arrest, awaiting trial.