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.

Michelle K. Anderson and Joseph Thomas McEnroe, both 29, entered the pleas in King County Superior Court. County Prosecutor Dan Satterberg is deciding whether to seek the death penalty if they are convicted of the charges.

Investigators have said that Anderson and McEnroe confessed to shooting to her parents, her brother and his wife and their two young children at her parents' home near Carnation, east of Seattle.

Prosecutors have given no motive, but said Anderson told detectives her brother owed her money and that 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.

The victims were Wayne Anderson, 60; his wife, Judy Anderson, 61; their son Scott Anderson, 32; his wife, Erica, 32; and their children, 5-year-old Olivia and 3-year-old Nathan.

Deputy Prosecuting Attorney James Conant asked Anderson and McEnroe whether they understood each charge against them. The defendants answered yes in barely audible voices, so quietly that Conant at one point said to Michelle Anderson, whose long brown hair hung down in front of her face, "I'm sorry, you'll have to answer out loud."

Their lawyers entered the pleas of not guilty on their behalf.

Family members of the victims and friends sat in the courtroom separated from the defendants by a pane of glass. They held each other and wept.

After the hearing, the family rushed out of the courtroom, down the hall and into an elevator without speaking to reporters and television cameras that followed them.

Judge Cheryl Carey set the next hearing in the case for Jan. 29.