Police say a woman and her husband became romantically involved with another woman, but tensions grew once the other woman moved in and the wife plotted with teenagers to kill the other two.

Anne Arundel County police say Ann Anastasi, a 13-year-old girl and the girl's 18-year-old boyfriend have been charged with first-degree murder in the deaths of Anthony Anastasi Jr. and Jacqueline Riggs.

Police say the Anastasis had been married for 18 years and Riggs moved into their basement over the summer. Anthony Anastasi and Riggs were found dead in the Lothian home Oct. 5.

Police say Ann Anastasi plotted with the 13-year-old girl and they recruited the girl's boyfriend to carry out the slayings.

Police initially called the deaths suspicious, but they've since been ruled homicides.