A woman accused of killing her pregnant friend three months after her own miscarriage was convicted Wednesday of beating and strangling the friend, then cutting the baby from her womb and passing the child off as her daughter. Julie Corey sobbed as a Worcester Superior Court jury found her guilty of the 2009 murder of 23-year-old Darlene Haynes. The jurors had deliberated for 10 hours over two days. Sentencing was scheduled for Tuesday. Prosecutors said Haynes was eight months pregnant when Corey attacked her and cut the baby out of her body. They told the jury that Corey had been pregnant, too, but had a miscarriage three months earlier.