(JTA) — On the third anniversary of the school shooting in Parkland, Florida, parents of the shooting’s Jewish victims shared their memories and hopes for the future.

Several of the 17 students and faculty who were killed in the 2018 shooting at Marjory Stoneman Douglas High School were Jewish. In the years since the attack, some of the victims’ Jewish parents have become prominent activists for gun control and school safety.

Fred Guttenberg shared a letter on Sunday that he wrote to his daughter, Jaime, on Twitter. Jaime was 14 when she was killed and would have graduated high school this year. Guttenberg wrote about his thoughts after the tragedy, and pledged to fight for stronger gun safety legislation in Jaime’s memory.

“Dear Jaime, 3 years ago your voice was silenced,” Guttenberg wrote. “You are on my mind every second of every minute of every day. I constantly relive your last seconds in my mind. Did you suffer? I will never know, but I fear that you did. Did I do enough to protect you?”

He added, “Because of what happened to you, our life has changed. Shortly after your murder, I embarked on a mission to do something about gun violence and this is now my life purpose and mission.”

Guttenberg is one of several Jewish parents of Parkland victims who dedicated themselves to activism due to the shooting. Max Schachter, whose son Alex, 14, was killed at Parkland, founded the nonprofit Safe Schools for Alex, and wrote on Twitter that “Today we remember Alex and honor his legacy… with your help we can continue our work to #KeepKidsSafe in schools.”

Lori Alhadeff, whose daughter Alyssa, 14, was killed in the shooting, has advocated for legislation to install emergency response mechanisms in schools. She wrote, “3 years ago my daughter Alyssa Alhadeff was shot & killed in her school. We must do more to http://MakeOurSchoolsSafe.org.”

Andrew Pollack, father of victim Meadow Pollack, 18, wrote “Thinking of all the Parkland families today more than ever.”

The gunman in the Feb. 14, 2018 attack killed 17 people at the school and injured 17 others. The shooting captured the country’s attention and galvanized a movement, led by the shooting’s student survivors, calling for stricter gun control measures. The movement culminated in the “March for our Lives,” which drew hundreds of thousands of protesters to Washington, D.C. and more to corresponding marches across the country.