Voice contestant opened her arms to hug murderer before he shot her dead

James Loibl and Christina Grimmie
James Loibl and Christina Grimmie

A US The Voice contestant who was killed by a gunman opened her arms to hug her murderer before he shot her dead.

Devastated fan Destiny Rivera, said she was at Christina Grimmie’s concert on Friday night and standing in line behind killer James Loibl at a merchandise table.

The 20-year-old told the Daily Mail she saw Grimmie getting ready to greet Loibl with a big hug when it was his turn to talk to her.

“(He) was walking up to meet her. Her arms were open, waiting to greet him with a hug,” Ms Rivera was quoted as saying.

“Then there was a sound of three pops, like balloons. People had brought balloons to the show and the security guards were popping them so at first I thought it was that.

“I saw Christina's leg fall to the side on the ground like a dead weight. I didn't see her face.”

Ms Rivera said Grimmie’s brother Marcus then leapt over a barricade to tackle the gunman and she turned and fled.

Loibl, 27, shot himself after he was knocked to the ground by Mr Grimmie.

Loibl had two handguns, two loaded magazines and a large hunting knife with him, NBC News reports.

Orlando Police Chief John Mina said Loibl lived more than 160km west of Orlando, and travelled there with the sole purpose of shooting Grimmie.

There was nothing to indicate Loibl knew Grimmie and it was possible he was a deranged fan, Mr Mina said.

Mr Mina told reporters Mr Grimmie was a hero in a "tragic event" and that his actions had possibly saved other lives.