"A child had left the residence out in the Thomas Bridge section of Smyth County and had gone to the neighbors to report that something was going on at their house next door... that there was possibly gunfire," Sheriff Chip Shuler told WCYB.
Deputies arrived on the scene to find the woman dead, along with the youngest and oldest child.
The six-year-old was critically wounded but still alive, and was flown to Johnson City Medical Center; but hours later the Sheriff's office confirmed the sad news the child had passed away too.
The eight-year-old, meanwhile, they said had managed to "escape the scene."
"The preliminary investigation shows that the adult female committed the homicide," investigators said, adding no additional suspects were being sought.