A woman and her boyfriend accused of killing six members of her family on Christmas Eve each pleaded not guilty Thursday to six counts of aggravated first-degree murder. Prosecutors are deciding whether to seek the death penalty if Michelle K. Anderson and Joseph Thomas McEnroe, both 29, are convicted of the charges. Investigators have said Anderson and McEnroe confessed to shooting her parents, her brother and his wife and their two young children at her parents' home in Washington state. Prosecutors have given no motive, but said Anderson told detectives her brother owed her money and she was upset because her parents did not take her side. She also said her parents were pressuring her to start paying rent for staying on their rural property.