Anderson was born in 1978 and lived in a mobile home on her parents' property at Carnation, in King County, Washington, with Joseph McEnroe. There was a long-running dispute about rent and about money she said her brother owed her.
On December 24, 2007 the two of them shot and killed her father Wayne, sixty, her mother Judith, sixty-one, her brother Scott and his wife Erica, both thirty-two, and Scott and Erica's children, Olivia, five, and Nathan, three. The parents were killed first; the rest of the family arrived later for Christmas Eve dinner and were killed as they came in. The bodies were moved and concealed on the property.
Both were arrested within days. The King County prosecutor announced in October 2008 that he would seek the death penalty against her, and abandoned that position in July 2015.
Neither was sentenced to death. McEnroe was convicted in 2015 and the jury declined to impose death; he received life without parole. Anderson's case was delayed repeatedly and she was convicted of six counts of aggravated first degree murder in 2016 and sentenced to life without parole. Washington's death penalty was subsequently struck down by the state supreme court in 2018 and abolished in 2023.
The case is a family annihilation and not a serial one, and it is in this archive under that qualification. The dispute at the centre of it involved a few hundred dollars of rent.