The message was sent hours after the 21-year-old singer was shot and killed in Orlando, Florida

'The End': Christina Grimmie's Twitter Account Hacked Hours After Her Death

Hours after Voice alum Christina Grimmie was shot and killed, her official Twitter account sent a mysterious message to her fans.

The 22-year-old singer, who placed in third on the NBC singing competition’s sixth season, was killed on Friday, after performing as the opening act for the band Before You Exit at The Plaza Live in Orlando, Florida.

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Witnesses say Grimmie was signing autographs and posing for pictures with fans when an unnamed gunman shot the singer. Grimmie’s brother Mark then wrestled the killer to the ground, before the shooter took his own life.

Grimmie’s Twitter account sent out a simple message on Saturday morning after the attack. However, Grimmie’s reps tell PEOPLE that her account had been hacked.

“The end,” the tweet reads.

Earlier on Saturday, new video of Grimmie’s final performance was released, showing the singer performing “Without Him” – a track off her self-titled EP, which was released in February.

Before her death, Grimmie promoted her upcoming show on Twitter, asking fans to attend the concert.

“ORLANDO!! Come out to the show tonight at the Plaza Live! Starts at 7:30,” she wrote hours before she was shot.

“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.”

Grimmie’s Voice coach Adam Levine expressed his sympathy in an Instagram photo of the two on Friday night.

“I’m sad, shocked and confused,” he wrote. “We love you so much Grimmie.”

“This just isn’t fair,” he added.