going to be places devices in one location, could he or she have placed devices in other locations. what are the ingredients, what is the person using, what other evidence might be there. in some instances you'll have letters left behind, for example, where someone is going to dictate what they did and what was going through their mind. if the person had a laptop computer, some kind of social media, some kind of medium that will allow investigators to get into the mindset of this person and dernetermine what it is the were doing and it's going to be very important for investigators to determine were there any pre-incident warning indicators that maybe others would have picked up on and didn't report that to law enforcement, really get a full picture of who this person is. it not just on other people, witnesses to provide information, law enforcement officers will go through their own holdings and determine is this someone known to us,