Alleged killer of The Voice star Christina Grimmie had two guns, knife

US singer Christina Grimmie in a 2011 file photo. PHOTO: EPA

MIAMI (AFP) - The gunman who fatally shot a young singer who once appeared on the popular TV show The Voice carried two handguns and a hunting knife at the time of the shooting, police said on Saturday.

Authorities said they believe that the 21-year old gunman travelled from elsewhere in Florida to Orlando, where rising star Christina Grimmie was holding a concert, intent on targeting her.

Grimmie, 22, performed late on Friday with the group Before You Exit at Orlando's Plaza Live Theatre and stayed after to sign autographs and sell merchandise.

The gunman approached her and opened fire without warning, then fatally shot himself, according to police.

Grimmie was rushed to the Orlando Regional Medical Centre, but died of her injuries.

In addition to the weapons, the shooter was carrying two loaded gun magazines, police said.

"The suspect in this case is not from Orlando. The suspect travelled to Orlando, apparently, to commit this crime, and then had plans to travel back to where he came from," police chief John Mina said during a press conference on Saturday.

Detectives are "going through the suspect's cellphone and computer to see if they can find a motive for this crime."

Mina said police are not releasing the suspect's name as the investigation continues.

Unarmed security guards at the concert venue conducted bag checks, police said, but somehow failed to discover the shooter's weapons.

"There are no metal detectors. People are not patted down. They open their bags and authorities look inside those bags for weapons," Mina said.

"I think it's important to note the type of crowd that attends this," said Mina, who said about 120 fans were still milling around the theatre when the shooting occurred.

"We're talking about young kids. This isn't a crowd that you would suspect would be carrying guns into a venue like this," he said.

Authorities said they were trying to figure out if the dead suspect might have known Grimmie, or if he was perhaps an obsessed fan.

The shooting seemed likely to add fuel to the long simmering debate over gun laws in the United States, where guns were used in more than 11,200 murders in 2013, according to the Centers for Disease Control and Prevention.

But past bouts of even more extreme gun violence, including the 2012 killing of 20 school children at an elementary school in Connecticut, have led to little change in a country where the right to bear arms is protected under the second amendment of the US constitution.

US Democratic candidate Hillary Clinton has vowed to take on the powerful US gun lobby if elected president, while Donald Trump, the presumptive Republican nominee, has promised "to cherish the Second Amendment."

Fans posted video clips on social media of Grimmie's performances, including her cover of Miley Cyrus' Wrecking Ball during a blind audition on The Voice.

A New Jersey native, Grimmie first gained public attention with moving covers of hit songs in videos viewed by millions on YouTube.

Grimmie, who competed in the sixth season of The Voice in 2014, released her debut EP Find Me in 2011.

"We are heartbroken," the NBC talent show said on its Twitter account after the shooting, calling the young singer "a loved member of our family."

"There are no words. We lost a beautiful soul w/ an amazing voice," it said after her death was confirmed.

Adam Levine, the singer whose team she performed with on the programme, posted a picture of himself with her on his Instagram account after the incident when the singer was taken wounded but still alive to the hospital.

"I'm sad, shocked and confused. We love you so much Grimmie. We are all praying hard that you can pull through this... this just isn't fair," he wrote, before news of her death became public.

Grimmie's own Twitter account still showed a video she posted on Friday asking fans to come out to see her perform, said Reuters.

Her account tweeted a simple message on Saturday morning: "The end."

However, a report on the People website quoted Grimmie's representatives as saying that the star's Twitter account had been hacked.

The post was retweeted more than 65,000 times within an hour.

Join ST's Telegram channel and get the latest breaking news delivered to you.