Mystery Knife

I was loading the dishwasher the other day and found an odd, bright pink kitchen knife that we do not own sitting in the dish rack. It was very late and quite dark, but I was able to make out that the knife was covered in something red. My first thought was, "Someone's trying to frame me for murder!" Then I calmed down and had a new thought, "I wonder if my wife killed someone? And if so, why didn't she run the dishwasher! Sheesh."