There are new details about the shooting at a Maryland mall over the weekend.
Darion Aguilar shot and killed two employees at a skateboard shop before turning the gun on himself.
The co-owner of the United Gun Shop where Aguilar purchased his weapon tells CNN the 19-year-old visited the shop twice in December.
On his first visit, Aguilar purchased a shotgun on for about $430 in cash, plus two boxes of ammunition.
A couple of weeks later Aguilar returned for another box of shotgun shells. But why Aguilar opened fire Saturday morning, killing two people before killing himself, remains a mystery.
CNN's Joe Johns is in Columbia Maryland with the latest.