Fourteen people were killed and 21 injured at the Inland Regional Center in San Bernardino, Calif. on December 2, 2015, during what has now become the worst mass shooting in the United States in three years. One of the victims, 27-year-old Sierra, was celebrating at a holiday party and expecting to receive an Employee-Of-The-Year award, when her life was tragically cut short by two murderers during the alleged terror attack.

Sierra’s father, stepmother and sister recall how they learned of her death, and share how they want Sierra to be remembered, in the video above.

“I feel that she is still with me, and she will always be with me,” Gregory, Sierra’s father says, wiping away tears. “We made a pact that we wouldn’t tell each other goodbye. We’d say, ‘See you later,’ because we knew we would always see each other again. And now, I can’t tell my baby girl, ‘See you later.’ I can’t tell her that.”