guns. >> reporter: police say the shooter was supposed to start classes at a community college today. police also say video cameras recorded at least part of the shooting, though it's not clear whether that's going to help them in determining a motive. don? >> joe johns, appreciate that, joe. joining me now hln law enforcement analyst mike brooks along with william pollack, an associate kline calling professor of psychology at harvard medical school. thank you guys for joining us. mike, i want to devote my first question to you. >> sure. >> in this case, like in new town, the shooter was living with his mother, but aguilar's mother said she saw no signs of any of this. how can someone in such close proximity not see anything unusual? >> well, i have a hard time believing it also, but many times, don, people who are closest to let's say the shooter, they might not recognize any signs, and, you