"Hmmmm. Perhaps. Perhaps" He walks towards the cutting board watching it carefully as the knife starts cutting into the wood. "Something terrible had to have happen inside here. For a poltergeist to be able to move objects like that takes a lot of energy. Most of the time most of this energy comes from anger caused by something terrible that to them or others they cared about. The fact they chose a knife to demonstrate that point seems to confirm that.  Still I could be wrong. I would  stay clear of that knife to be on the safe side."