What caused Sandy Hook Elementary Schol shooter Adam Lanza to go on his killing rampage? In new details, investigators say Lanza may have been in “direct competition” with Anders Behring Breivik, the Norwegian man convicted of a bombing and massacre at a summer camp in that country.

Law enforcement officials have come up with this theory because they found several articles about Breivik in Lanza’s bedroom.

Tonight Frontline and The Courant present an investigation into the young man and his mother and how his actions rocked the town of Newtown in the documentary “Raising Adam Lanza.” It airs on GPB at 9 p.m. It’s a thought provoking piece that can be used to spark honest discussions on school violence and how to deal with it.

In light of recent school shootings at Atlanta’s Luther J. Price Middle School and Clark Atlanta University, these conversations are sorely needed. “Raising Adam Lanza” is part of PBS’s initiative “After Newton” that includes documentaries, news reports and public affairs shows on gun violence.

Watch a clip.