individual. we don't know what drove him to this. i believe over the next few days, we will learn more about him, his background, his personality, what other prior histories he may have had as well. >> what's the work that's being done outside of that interrogation room with this suspect? >> a lot has been done, particularly around the forensic side. there are going to be search vehicles around his residence that he lived in or may have lived in. what he owned or operated. we're going to get a lot more assessment from his family and friends. this is going to be a longstanding investigation. for a number of reasons, one for prosecutorial residence. one, we need to know from a psychological perspective. how did he get to this, if opportunities present themselves, oftentimes, they do