Killer: The gunman who shot dead Voice star Christina Grimmie has been identified as Kevin James Loibl

Relatives of the man who shot singer Christina Grimmie dead at a concert last night before killing himself have apologized for the murder in a note stuck to their front door.

Kevin James Lobil, 27, drove from his home in St Petersburg last night to a Grimmie concert in nearby Orlando armed with two handguns and a knife before opening fire as she signed autographs for fans, police say.

This afternoon a hastily-scribbled note was found pinned to the door of his house, which he shares with his parents, which says: 'Deepest sorrow for lost [sic] to the family, friends and fans of the very talented, loving Christina Grimmie. No other comments.'

Meanwhile witness Destiny Rivera, 20, told Dailymail.com that she was standing behind the shooter as he walked over to Grimmie at a merchandise table after the gig.

Rivera said that Grimmie was standing with open arms waiting to give him a hug before he opened fire.

While officers have not yet attributed a motive to the killing, Orlando police chief John Mina said it is 'looking like' Loibl was a deranged fan of the singer.

Grimmie had been performing as an opening act for band Before You Exit at The Plaza Live. The concert finished at 10pm and she was signing autographs at a merchandise table when Loibl approached.

Mina said that the 27-year-old gunman had traveled to Orlando from St Petersburg, around a two-hour drive away, specifically to kill Grimmie.

He said the suspect did not know her, despite coming to the concert armed with two handguns, extra magazines and a knife.

He added that Loibl had plans to travel home after the attack, but did not reveal how cops know this.

The venue where the concert was held has unarmed security guards who check bags and purses for weapons when people enter the building, but there are no metal detectors.

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This note was found tacked to the door of the home Loibl shared with his parents in St Petersburg, Florida

Tragic: Singer Christina Grimmie was fatally wounded at around 10.30pm Friday after a concert (above) at the Plaza Live theater in Orlando. The shooting happened as she signed autographs for fans

Hero: Christina's brother, Mark Grimmie (pictured with his sister), was hailed a hero by police for tackling the shooter and stopping any further bloodshed. He was sadly unable to save his sister. Right, concert-goer Destiny Rivera thanked Mark for saving her life

During a press conference on Saturday, Orlando Police Chief John Mina (pictured) said the gunman was a 27-year-old white male who traveled to Orlando from another city in Florida to specifically kill Grimmie

Police say Loibl, who did not know his victim personally, drove from his house in St Petersburg, Florida, to the concert where he shot Grimmie as she signed autographs for fans

Rivera told Daily Mail Online she had been standing behind the shooter in the queue of fans waiting to meet Grimmie after the gig.

She said: 'Christina was hanging out by the merchandise table, near the sound desk,’ Destiny said. 'She was talking to fans and taking pictures.

'I had made friends in line with some other fans and my group were talking to them. Two people were meeting Christina and there was one guy in front of us in line.

‘When he was walking up to meet her, her arms were open, waiting to greet him with a hug.

‘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.

‘Then I saw the yellow barricade fall and the two people who had just met her started running away.

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

Selena Gomez paid tribute to Grimmie, who she met through her agent stepfather, saying 'my heart is absolutely broken'

‘I saw her brother jump over the merchandise table and then it was just a blur. I turned and started running, then I heard another pop.'

Speaking about the shooter, she added: 'He seemed nervous. He was there by himself, looking around and moving, like he was trying to find something to do because he was on his own.

'He looked kind of creepy. He seemed around our age. He had no bag with him but had on a black hat and a red and black flannel shirt.'

Rivera mentioned that she and her friends had arrived late to the gig and were waved through security without being patted down or having their bags searched.

She added: 'I want to say a personal thank you to Christina's brother, Mark. Since the shooter had so many weapons on him, it makes me wonder what he actually had in mind.

'It also pains me to think, "what if Mark didn't tackle the shooter?" Mark definitely became a hero last night. His brave, strong soul was able to save the life of my friends, Christina's other beloved fans, and myself.

'Because of him, my friends and I made it out of the venue safe and alive. 'I am so grateful that people like Mark exist in the world because he was able to risk his life to save others and he did not have a second thought about it.

'I have so much love and respect for him and although I may never get the chance to let him know in person, I still want him to know that I am thankful for everything he did for me that night.'

Dan Erickson, 38, a neighbor, who lives close to the Loibls house, told the Tampa Bay Times that he rarely saw the son, but that his father was 'very nice'.

He added: 'When a tree fell down on my house, he was the first person to come over and make sure we were okay.'

Marcus Grimmie, Christina's brother who also goes by the name Mark, paid tribute to her on Facebook this afternoon, saying she was his 'partner in life'.

He wrote: '[She was] a superstar. A goofball. Introverted. And a friend to everyone. Genuinely. But above all...she was my baby sister.

Mourners today returned to the spot where The Voice singer was killed in order to law flowers

Several people wept as they paid their respects to Grimmie, who died aged 22 after being shot

Members of the Velazquez family, who were fans of Grimmie, weep as the visit the venue where she died

At midnight on Saturday more mourners arrived to hold a candlelit vigil outside the music venue

Fans former Grimmie's initials out of candles along with a heart as others laid flowers or brought balloons

Signs on the doors of the venue show a 'no concealed weapons' policy, though witnesses say they were not searched on the way into the premises

'She loved the Lord and her family and was always there for me and I honestly don't know what I'll do without her.'

Meanwhile a source told People that Mark, who acted as Grimmie's tour manager, 'had a really loving relationship' with her and that the pair 'had each other's backs'.

The source added: 'They basically hung out the entire time. You could tell they were sort of a team.

'There was a lot of laughter in between takes, during takes – they were joking back and forth. It was a really good vibe.'

Fellow singer Selena Gomez also paid tribute to Grimmie, who she met through her stepfather Brian Teefey.

Teefey served as her agent after discovering her on YouTube.

The Hands to Myself singer wrote on Twitter: 'My heart is absolutely broken. I miss you Christina.'

Meanwhile another witness described the horrific events play out and said the room went 'f***ing crazy' after shots were fired.

Karla Abel told People Magazine that Grimmie had been interacting with fans post-concert at 10.30pm Friday and that the atmosphere was 'super normal' and 'happy'.

The 22-year-old singer was standing by a table surrounded by people, including band Before You Exit, at a merchandise table and there was a 'good vibe', explained Abel.

She then heard the sound of 'six or seven' gunshots which she thought at first were firecrackers.

Seconds later, the room descended into chaos.

Abel said: 'People were throwing themselves onto the ground, and covering their heads.

Scene: Authorities are unclear of how the attacker was able to make it inside The Plaza Live (above) with two guns and a hunting knife

Orlando Police later confirmed her death on Twitter and wrote the above message

Devastated fans outside the Plaza Live Theater on Bumby Avenue in Orlando wait for news after the shooting

Mortally wounded: Grimmie was shot in the head by the attacker who was tackled by her brother before shooting himself, witnesses said. No-one else was harmed

'All I could do was look at the exit doors and duck and run out. But it was terrifying. Everyone was screaming.'

Between the crowds of people who were ducking on the floor, Abel said she saw Grimmie's feet, which weren't moving.

She said she didn't see any blood, but thinks her friend did.

Brother Mark, then tackled the heavily-armed gunman before he killed himself in front of about 60 children and teenagers.

The teens were then evacuated from the Plaza Live Theater by security and told to wait outside until police had arrived.

The singer was taken to Orlando Regional Medical Center in a critical condition; one witness said he saw her bleeding from the head and being given chest compressions.

The gunman died on the scene and no one else was hurt during the shooting. At 2.45am Grimmie's publicist confirmed the star had died from her injuries.

'It is with a heavy heart that we can confirm that Christina has passed and went home to be with the Lord. She was shot at her show in Orlando and, unfortunately, didn't survive the gun shot wounds,' she said.

Tragic: Adam Levine, a coach on The Voice, shared a photo (above) to Instagram of him smiling with the brunette beauty and wrote that he's 'sad and shocked' by her death

Singer Demi Lovato was one of many who tweeted tributes in the wake of the shooting

Nick Jonas posted this picture of himself and Christina Grimmie, on Instagram after hearing of her death

Today we lost an angel, sister, and a beloved friend. #RipChristina pic.twitter.com/EkwTKsaLFr — Before You Exit⇞ (@beforeyouexit) June 11, 2016

'We ask at this time that you respect the privacy of her family and friends in their time of mourning. If you'd like to give back to Christina's family in her memory, please consider donating to the families GoFundMe page in their time of need.'

Police are checking the man's cell phone, computer and social media to see if they can find a motive for the horrific shooting and say he has no prior criminal history that they are aware of.

Not long after the news of her death emerged online, #RIPChristina started trending on Twitter, with celebrities, friends, and fans paying tribute to the young woman.

Adam Levine, a coach on The Voice, shared a photo to Instagram of him smiling with the brunette beauty and wrote: '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.'

Singer Demi Lovato took to Twitter and wrote: '#RIPChristina my thoughts and prayers are with her loved ones..'

Nick Jonas also shared a photo to Instagram showing a beaming Grimmie next to him and wrote: ' #ripchristina' before a broken heart emoji.

The band who she played with Friday night shared a long tribute to her on Twitter and wrote that they lost an 'angel, sister and beloved friend.'

'Christina was such a loving, caring, beautiful person with the biggest heart. She was an absolutely incredible musician and an even better friend,' the band tweeted.

NBC's The Voice paid tribute to the singer on Twitter not long after news of her death emerged

The Voice wrote that she was a 'loved member of our family'

Actress Ariel Winter also paid tribute to the singer on Twitter and wrote the above message

Actress Hailee Steinfeld, who appeared in True Grit and Pitch Perfect 2, tweeted this tribute

'We are so saddened by her passing and are completely heartbroken.

'Words fail to describe how much Christina means to all of us. She was always a constant beam of light and energy into the hearts of everyone around her.

'Her carefree 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.

'Please join us in keeping Christina's family in your prayers as we know Jesus said, 'In this world you will have trouble. But take heart! I have overcome the world.' She and her talent will be missed by us all,' the band added.'

NBC's The Voice tweeted: 'There are no words. We lot a beautiful soul with an amazing voice.

'Our hearts go out to the friends, fans and family of @TheRealGrimmie. We are heartbroken. @TheRealGrimmie is a loved member of our family.

'Our thoughts are with her and her family. #PrayForChristina'

Before: Grimmie, who has a strong presence on YouTube and social media, had attracted a number of children and teens to the concert - many of whom were present when she was shot

Actress Ariel Winter also paid tribute to the singer on Twitter and wrote: '#RIPChristina -another senseless act of violence against a soul so beautiful...everyone please send support and love to her family.'

Actress Hailee Steinfield, who appeared in True Grit and Pitch Perfect 2, tweeted: 'At a complete loss for words. Unbelievable. My heart breaks over the news.'

Josh Call told The Orlando Sentinel he was outside the venue working at a vegan hot dog stand when he heard four or five gunshots.

'It was quick like pow, pow, pow, pow,' he said, adding that a security guard jolted at the sound and ran inside to find out what happened.

Call told the paper he waited outside, and went inside where he saw 'a female' on the ground with blood coming out of her head, and someone giving her chest compressions.

A man with a 'disfigured' face lay dead nearby, he said.

Star: Grimmie is best known for finishing third on the 2014 season of The Voice (left), and had built up a following on YouTube

Christina Grimmie, seen here with Carson Daly, came in third on the sixth season of The Voice in 2014

One person claimed in an Instagram and Facebook post that Grimmie was hit three times, but this could not be confirmed.

As many as five gunshots were fired, reported.

'We were waiting out there to go see (Grimmie) come out at the back of the venue, and then we just saw security running,' Juana Villegas told The Orlando Sentinel.

'Then a girl comes out hysterically crying and she said that someone shot themselves next to her,' she said.

Fans initially sent messages of support and good wishes on social media using the hashtag #prayforchristina but that changed to #RIPChristina when it became clear she had died.

Grimmie is known for covers of pop songs including Nelly's 'I Have a Dream'.

Her YouTube videos - under the name zeldaxlove64 - have as many as 17million views.

During her 'blind' audition for The Voice, she sang Miley Cyrus' Wrecking Ball and received amazing reviews.

Christina Grimmie, seen here appearing on a radio show last year, signed a contract with Island Records after appearing on The Voice but her only album, With Love, came out in 2013

Christina Grimmie performs onstage at the iHeartRadio Music Festival at the MGM Grand Garden Arena in Las Vegas in September

She chose Maroon 5's Adam Levine ad her mentor for the show and went on to place in third in the singing competition for season six.

While on the show she received public support from megastar Justin Bieber.

She was signed to Island Records but was later dropped by the label.

Gun control is due to become a major issue in the presidential election in November with Democratic nominee Hillary Clinton promising to tighten the laws and impose more background checks on people buying guns.

Florida has some of the most relaxed gun laws in the country.

Anyone over the age of 18 can buy a shotgun or a rifle without the need for a permit and anyone over 21 can buy a handgun - after a three-day waiting period - as long as they are not a convicted felon, a drug addict or have been 'adjudicated mentally defective or involuntarily committed by a judge'.

When it became clear Grimmie had died there was an outpouring of emotion on Twitter

News of the shooting and Grimmie's death broke very late Friday but Twitter was still inundated with tweets