Tributes have popped up across the internet following news that singer Christina Grimmie died at the hands of a lone gunman after a performance Friday night in Orlando, Florida. She was 22.

Grimmie was shot while signing autographs at The Plaza LIVE. She and pop-rock band Before You Exit performed at the venue.

Grimmie's brother tackled the shooter, who died of a self-inflicted gunshot wound, according to police. She was rushed to the hospital, where she was pronounced dead.

Authorities have not identified the shooter or a motive behind the attack.

Fans and friends mourned the singer on social media. In a statement posted on Twitter early Saturday, Before You Exit said its members were "completely heartbroken" by her death.

"Words fail to describe how much Christina means to all of us," the band wrote. "She was a constant beam of light and energy into the hearts of everyone around her. Her care-free spirit and her laughter constantly lit up every room she entered and she always had this glisten in her eyes, which was evident in her faith.

"While we know there is no sort of feeling that can replace the joy Christina brought into our lives, we know she is glistening from up in Heaven and shining down on all of us."

Before news of Grimmie's death was confirmed by her publicist and police around 3 a.m., singer Adam Levine posted a photo with Grimmie on Instagram. Levine was Grimmie's coach on "The Voice" when she competed in 2014. She placed third in the competition.

"I'm sad, shocked and confused," he wrote. "We love you so much Grimmie."

Other fans and friends also paid tribute, including Justin Timberlake, Demi Lovato and Nick Jonas.