There has been a lot of talk about what parents should do if their children have mental issues.
Adam Lanza's first victim was his mother Nancy Lanza, who family and friends say struggled with a son who had increasing emotional and behavioral issues.
"She constantly tried to help him and get help for him and she did what she could as a mother," Mark Tambascio, Nancy Lanza's friend, said.
Mothers like Tami Roberts are still trying to make sense of crimes committed by their own children. Her son Jacob just last week went on a shooting spree at an Oregon mall.
"I'm so sorry for Jake causing so much pain and trauma. Never could I imagine him being such a part of something like this but as his mother he will always be in my heart," Roberts said.
What drives a teenager to commit such violence?
Dr. Jonathan Fast is a professor at Yeshiva University and the author of "Ceremonial Violence," an analysis of 13 school rampage shootings.
"The ceremony is the shooting or the end of domestic terrorism that they arrange as their last event on earth," Dr. Fast said.
He says it often begins with a strong sense of shame; one they believe can't be solved that leads to suicidal thoughts.
"Once you made that decision you have a whole number of options open to you that you can commit without consequence because you're not going to be there," Dr. Fast continued.
Dr. Fast says often the troubled teens have similar characteristics.
"We have children who tend to be very isolated tend to be very unusual, so they get bullied a lot," Dr. Fast said.
Adam Lanza's former classmates described him as being different.
The school's former security director Richard Novia, who was close to Lanza, says the young man could feel neither emotional nor physical pain.
"If he cut himself or hurt himself he would not know it or feel it," Novia said.
But moving forward, one mistake we need to avoid is profiling children. Just because a teenager is awkward or withdrawn, does not mean they will commit a crime like this. Assuming that can be very damaging, we saw that happen after other incidents like Columbine.
Get Eyewitness News Delivered