RHINELANDER, Wis. (AP) — A northern Wisconsin teenager accused of killing her mother and stepfather has pleaded guilty in a plea deal that has prosecutors recommending a 40-year prison sentence.

Eighteen-year-old Ashlee Martinson entered her plea on Friday to two counts of second-degree homicide. The teen had earlier pleaded innocent by reason of insanity.

Martinson was accused of fatally stabbing 40-year-old Jennifer Ayers and shooting 37-year-old Thomas Ayers at the family’s home near Three Lakes in March 2015.

Investigators said Martinson confined her three sisters in a room before fleeing to Indiana with her boyfriend. Court documents say the Ayerses were killed the same day they warned Martinson’s 22-year-old boyfriend to stay away from her because she was a minor.

The sisters, ranging in age from 2 to 9, weren’t hurt.

Jennifer Ayers is a New Jersey native who grew up in Hays and graduated from Hays High School and Fort Hays State University.

For up-to-date coverage of the developing story from the Wausau Daily Herald’s Nora G. Hertel, click HERE.