What was the official explanation for the beheadings in the car crash?

I think that's why it was opened as a homicide later on. A couple people where probably like "Oh, that's kind of weird" so the Detective got the case reopened. I'm not sure if Ты remember but in one of the season's (first I think) Juliette had the old Detective who was on the case call Nick and he said, "One of the most frustrating cases I've ever worked on" или something to that degree...