Talented young songstress and former The Voice star Christina Grimmie was shot dead as she signed autographs after a concert in Orlando, Florida.
Christina built up a strong following online by posting videos of her singing on YouTube before entering series 6 of the US version of the Voice, where she was mentored by Adam Levine and received support from Justin Bieber and Lil Wayne.
Christina posted a video message on her Twitter account just hours before the fatal incident, letting fans know that she would be performing in Orlando that evening.
Clips of Christina's last performance have also surfaced online, showing the young singer in her element on stage.
The band performing with Christina on the night of the attack, Before You Exit, posted a moving tribute - describing their late friend as "a constant beam of light and energy".
Her former mentor Adam Levine also shared a picture of the pair.
Other famous fans and friends shared in their shock and sorrow on Twitter.
Many members of the YouTube community have also flocked to Twitter to remember the immensely talented young singer.