What is Abigail's exact threat to the other girls?

Here is the quote,

"And mark this. Let either of you breathe a word, or the edge of a word, about the other things,and I will come to you in the black of some terrible night and I willbring a pointy reckoning that will shudder you. And you know I cando it; I saw Indians smash my dear parents' heads on the pillow nextto mine, and I have seen some reddish work done at night, and I canmake you wish you had never seen the sun go down!She goes toBetty and roughly sits her up.Now, you—sit up and stop this!"