Transcript for Sandy Hook Promise Launches New PSA on How to Know the Signs and Prevent Gun Violence
Let's look ahead now because we are here with Nicole Hockley. Four years ago this month she lost her 6-year-old son Dylan in the sandy hook shooting and now on a mission to prevent that kind of violence and she's founding the sandy hook promise that just produced a new psa to recognize the warning signs that could trigger violence. They are easy to miss. Watch this closely. See if you can catch then. It includes a moment that may not be appropriate for small children. Take a look. ??? He was never sure just how long he would last ??? ??? but there's not much love in a lonely room today is the day that Johnny met June ??? Have a good summer. You too. Thanks. He must be bored. This is the guy that I was writing to in the library. Yeah, guilty. My god. So you like to write on desks. Yeah. And Nicole Hockley joins us now. We saw that image right at the end but there was so much else going on in that psa. I could barely pick the stuff up. Tell me what we missed. Some of the signs we missed in that video were a student in the background studying a weapons magazine which is a sign. We also saw the student being bullied in the hallway which is another warning signal and finally we saw the student studying other shootings and how to use these firearms. These are the signs that could easily be overlooked by parent, by teachers, what should parents be looking for? Parents should be looking for any sort of extreme changes in their children, so this could be excessive anger over or aggress over a minor incident. It could be an extreme behavioral or anti-social behavior or excessive isolation and chronic bullying. These are all signs and signals and, of course, any overt threat, someone who is writing something or showing a picture of violence. Without the overt threats, I mean, sometimes these behaviors can be triggered by other things as well but those are the kind of flags that go up. What should parents do when they happen. Parents should take it seriously and get help immediately. Don't ignore these signs and signals, get your child help. Talk to the school. Talk to local law enforcement. Talk to a mental health professional but don't just think it's going to go away. If you're concerned about a behavior you're seeing, get help. Gets a little trickier when it's someone else's child. Yes. What can you do? You have to talk to that other parent. It is absolutely and critically important that parents talk to each other. If you're seeing signs and signals, do something about it if a parent isn't prepared to listen to that from you, then go seek help elsewhere but don't be that person that walks away and thinking, someone else will take care of it or someone else will do something. Do something yourself because if you don't take action, it could lead to tragic consequences. You have been doing so much to honor the memory of your son Dylan. What do you hope comes out of this. I want parents to know that gun violence and violence is preventible when you know the signs. This isn't something that we should walk away from or look away from. It's something that we need to be up standards about and take action on because these are action that is can save thousands of lives. My son's death was preventable. Other deaths are preventable as well. Thank you for being on this mission. Thank you, George. See the full psa at goodmorningamerica.com on Yahoo!
This transcript has been automatically generated and may not be 100% accurate.