Grimmie, who came in third on the NBC singing competition' sixth season, was fatally shot on Friday evening after performing at The Plaza Live in Orlando, Florida.
The 21-year-old singer had just opened for the band Before You Exit. Witnesses say she was signing autographs and posing for pictures with fans when an unnamed gunman shot the singer. The killer was then wrestled to the ground by Grimmie's brother, Mark, and took his own life.
Video of Grimmie's performance hit YouTube early on Saturday morning. In the clip Grimmie sings "Without Him" – a track off her self-titled EP, which was released in February.
"I'm just imagining a life without my baby," Grimmie sings in the track. "And I know, I know, this life ain't meant to be lived without him."
As news spread of her death, alums of The Voice took to Twitter to express their sympathy, including current champ Alisan Porter and fellow coach Blake Shelton. Fans took to the hashtag #PrayforChristina with their memories of the young artist.
"I'm sad, shocked and confused," Grimmie's Voice coach Adam Levine wrote in an Instagram photo of he and his mentee. "We love you so much Grimmie."
"This just isn't fair," he added.
A GoFundMe page has been set up to support Grimmie's family.