'The Voice' star Christina Grimmie was shot dead by a man who traveled to Orlando to kill her

Christina Grimmie, a star on "The Voice" and a popular YouTube singer, was shot and killed Friday night after a concert in Florida in what police say was a planned killing.

Grimmie was signing autographs and interacting with fans after her concert at the Plaza Live in Orlando when a man approached and fired around 10:30 p.m.

Grimmie, 22, was rushed to the hospital in critical condition and died shortly after.

The shooter, an unknown 21-year-old man, had traveled to the concert, and had "plans to travel home" afterward, indicating he had deliberately targeted Grimmie, according to Orlando police Chief John Mina.

Grimmie's brother, Marcus, tackled the shooter to the ground, and the shooter subsequently turned the gun on himself, Mina said.

"Marcus' heroic actions may have prevented further loss of life," said Mina.

The shooter was carrying two loaded small-caliber handguns, two loaded magazines, and a large hunting knife, police said.

There were around 120 people in the venue when the shots were fired, but there's no video footage that police are aware of, according to Mina.

The Plaza Live had unarmed security guards on site, though no pat-downs were conducted at the door.

The investigation is ongoing, and Mina said he expects more details regarding the shooter's name and possible motives to be released later on Saturday.

Orlando detectives will be searching the shooter's apartment, as well as his computer and phone for possible social-media contact with Grimmie.

There has been an outpouring of grief on Twitter for Grimmie's passing: