By Madison Park, CNN

(CNN) -- In the span of a week, three suicides have devastated two communities that already shared a tragic connection.

Two were young survivors of the massacre at the school in Parkland, Florida, and one was a parent of a child who was killed in the Sandy Hook shooting. The two communities are facing a new facet of grief after three people connected to the shootings took their own lives in a matter of days.

Here's a look at their stories.

Jeremy Richman

Jeremy Richman, 49, was the father of 6-year-old Avielle Richman, who was among 20 children and six adults killed in the 2012 Sandy Hook Elementary School shooting in Newtown, Connecticut.

After the shooting, Richman co-founded The Avielle Foundation, a nonprofit named for his daughter that focuses on violence prevention through research and community engagement.

He died of an apparent suicide and was found in his Connecticut office building Monday morning, Newtown police said.

"Jeremy's mission will be carried on by the many who love him, including many who share the heartache and trauma that he has suffered since December 14, 2012. We are crushed to pieces, but this important work will continue, because, as Jeremy would say, we have to," the foundation said.

Sydney Aiello

Sydney Aiello, a 2018 graduate of Marjory Stoneman Douglas High School, survived the attack on Valentine's Day 2018 that killed 17 people at the Parkland, Florida, school. Aiello was reportedly close friends with Meadow Pollack, one of the 17 killed.

Aiello's mother said her daughter suffered from survivor's guilt and had been diagnosed with post-traumatic stress disorder, according to CNN affiliate WFOR. She graduated just months after the shooting and was attending Florida Atlantic University.

She killed herself on March 17. Her funeral was Friday in Davie, Florida.

Unnamed Parkland student

On Saturday, a Stoneman Douglas student died in what police describe as "an apparent suicide." The student has not been publicly identified. CNN affiliate WFOR and the Miami Herald reported the student was a male sophomore.

It's unclear under what circumstances the student died, or whether the apparent suicide was related to last year's massacre.

The news of the student's death came as the Parkland community is mourning Aiello and prompted discussions among community leaders, the school district and parents about how to address what trauma survivors are facing.

If you or someone you know might be at risk of suicide, here's how to get help: In the United States, call the National Suicide Prevention Lifeline at 1-800-273-8255. The International Association for Suicide Prevention and Befrienders Worldwide also can provide contact information for crisis centers around the world.