We've had serial killers in the past. [Simply; when it is a tool, you get people who misuse it. It's a fact.
She hmms at his question though, both thinking it over and wondering what prompted that specific one]
If I try at it, I could do something like that, I suppose. What "kind" is almost irrelevant on my world-- nearly everyone uses the same thing, just to varying levels of skill and ability-- but I can tell the difference between it and someone else's power. How much is possible, if they're not concealing themselves, but most do partly to avoid that.