Cavitt (D) dated Mianta whose mother, Betty, disapproved of the relationship. Mianta became upset that she was not allowed to go on dates with D. Around the end of November 1995, 17-year-old Mianta, 17-year-old D, and D's friend, 16-year-old defendant Robert Williams, developed a plan to burglarize the house, where Mianta was then living. They were going to tie up Betty and steal what they could find. Mianta purchased rope and packing tape on the way home from school. She placed a bed sheet outside the house and left the side door unlocked. D and Williams drove to the house. They were wearing black clothes, gloves, and hockey masks and were carrying duct tape. Mianta met them at the side door, gave them the rope she had just bought, and told them Betty was upstairs in bed. D and Williams threw the sheet over Betty's head. They tied her up and also punched her in the back with their fists to get her to be quiet. She sustained extensive bruising to her face, shoulders, arms, legs, ankles, and wrists, consistent with blunt force trauma. All three then robbed the house. D and Williams pretended to bind Mianta and placed her on the bed next to Betty. Betty was still breathing, although with difficulty when they left her, face down on the bed. Mianta freed herself and removed duct tape from Betty's mouth. Betty did not move and did not appear to be breathing. Mianta claimed that robbers had entered the house while she was downstairs watching television, had put a sheet over her head, and had knocked her unconscious; that she was eventually able to free herself; that she had called her father to report the crime; and that her stepmother was unconscious. Police arrived, and Betty was not breathing and had no pulse. The cause of death was insufficient oxygen, or anoxia, caused by asphyxiation. Mianta eventually confessed to her involvement in the burglary-robbery. D and Williams were arrested on December 2 and also confessed. D and Williams both contended that Mianta must have killed Betty after they had left. D and Williams were convicted of first-degree murder with the special circumstances of robbery-murder and burglary murder, as well as certain lesser offenses.