After that tragedy, President Barack Obama spoke to the nation about reducing gun violence.
"We're going to need to work on making access to mental health care at least as easy as access to a gun," he said five days after the deadly shooting.
The Behavioral Threat Assessment Center has not been promoted by the White House as one of its major efforts to reduce gun violence. Instead, it's continued the behind-the-scenes work it's been doing for the past three years. And referrals keep coming in.