Families of Sandy Hook victims release new PSA

A group of families who lost children in the Sandy Hook school shooting have released a new public service announcement.
It's part of their "Know the Signs" campaign.
They say if you watch the video closely, you'll notice in the background a student reading a gun magazine.
They say a lot of people miss similar signs about their own classmates.
The group says it wants to teach people to recognize the warning signs of someone who might be thinking about gun violence.