Suicides highlight mass shooting survivors' trauma: 'We still live with it every day'

Two teenagers who survived a high school mass shooting in Florida and a parent of a girl killed in an elementary school mass shooting in Connecticut died by apparent suicide within the last 10 days, prompting calls to focus on the lasting trauma of these attacks, which doesn't end with the gunfire.

It has also put the spotlight on how tenuous healing can be -- with survivors who may seem to have turned a corner in their grief instead befalling tragedy.

More than six years after his 6-year-old daughter, Avielle, was murdered at Sandy Hook Elementary School in Newtown, Connecticut, along with 19 other children and six educators, Jeremy Richman was found dead Monday from an apparent suicide, according to police.

"Jeremy was a good friend," Sen. Chris Murphy, D-Conn., told ABC News on Monday. "He was someone so committed to understanding why these tragedies happen and why brains push people to acts of violence."

After the shooting, Richman, a neuro-pharmacologist, founded a nonprofit "to study the neuroscience, the underpinnings of violence and the risk factors," he told the ABC News podcast "10% Happier" last year.

Murphy said Richman was at his office a few weeks ago and appeared "so excited about the work the foundation was doing and their ability to get their training program -- teaching about the way that the brain works and the way that it can fail to work properly -- to more and more people."

"Every single time somebody commits suicide, you can't understand it," Murphy said. "But in this case, Jeremy spent his entire life trying to help people identify the warning signs of harm. And it tells you how complicated the brain is, that even Jeremy couldn't figure out a way to get himself the help that he needed."

For friends and family who notice any of those warning signs, Burgess recommends these steps:

-- Ask if they are thinking of killing themselves in an "honest dialogue."

-- "Work to keep them safe," he said. "If the person is suicidal or in crisis, help them develop a safety plan including trying to remove any access to lethal means."

-- "Be there. Whether that's in person or on the phone ... listen to them without judgment," he said. "Give assurance that you're supporting them and they're not alone."

-- Help the person in crisis connect with available resources. Strengthafterdisaster.org is one resource Burgess recommends.

--Follow up and keep asking how they are doing. If they are still struggling, return to those first steps.

Franco recommends the Columbia Protocol to help determine when someone is at risk for suicide. The Columbia Protocol offers these six questions for teenagers and these six questions for parents.

Mendo, the Columbine survivor, now works with The Rebels Project, which helps mass shootings survivors find a support system. One of The Rebels Projects' new initiatives is a network for survivors to use as a tool kit, she said.

"It gets very comfortable to back away and become more secluded. My advice is to do the opposite. Go find somebody, find a person. Find us at The Rebels Project. Find something that you're comfortable with being around and talking to just find somebody to talk to," Mendo said.

"Recovery takes time," Burgess said, "and recovery is possible with ongoing care and support."

ABC News' Brad Mielke, Victor Oquendo, David Rind and Scott Withers contributed to this report.