By CBS3 Staff

UPPER MAKEFIELD, Pa. (CBS) – A mother who allegedly shot and killed her two young sons in Upper Makefield last week is now facing first-degree murder charges. Police say 38-year-old Trinh Nguyen shot both of her sons in their beds last Monday and attempted to shoot a neighbor.

Mother, Trinh Nguyen, Charged With Murder In Fatal Shooting Of Two Young Sons, 9 And 13

The boys, ages 9 and 13, were pronounced dead on Friday.

2 Young Brothers Pass Away After Being Shot By Mother In Upper Makefield Township

Detectives say Nguyen planned the killing, leaving a handwritten will instructing what to do with her and her sons’ remains.

Nguyen was denied bail and is behind bars.