Im pretty sure she was just using the witch killing spell, and then decided to stop. This is because she said something along the lines of "no, I shouldn't kill you. I have something much better." EmpyreanSmoke (talk) 18:09, March 26, 2015 (UTC)
The Latin incantation indicating if this spell is little different in use:
"Cruciatus letumque" roughly means "torture (until) death"