Christina Grimmie delivered a powerful video performance Saturday night on twin screens in the Medford church where she, her parents, and older brother worshipped before fame and stardom called her to California.

Wearing headphones and playing a keyboard, the deeply religious young woman sang the prescient words of the hymn "In Christ Alone":

No guilt in life

No fear in death;

This is the power of Christ in me.

She ended with "Till He returns or calls me home."

The rapt, sometimes tearful, congregation of 500 at the Fellowship Alliance Church listened with sorrow. The young woman they had watched blossom into a national singing sensation on NBC's The Voice had died a day earlier, cut down by a gunman as she signed autographs after a concert appearance in Orlando, Fla.

The hymn, "one of my favorite songs ever," she explained, had been videotaped for Easter 2012, apparently like dozens of Grimmie's performances - in a home studio with a Sonic the Hedgehog poster in the background.

The congregation burst into applause as the video finished.

Elder Bryan Russell and senior pastor Marty Berglund led prayers for the Grimmie family, her mother and father, Tina and Albert, and her brother, Marcus.

Christina Grimmie, Berglund said, is now in heaven.

Orlando police said the man who traveled more than 100 miles to kill her was Kevin James Loibl, 27, of St. Petersburg, Fla. They said he armed himself with two small-caliber handguns, two loaded magazines, and a large hunting knife.

Loibl apparently did not know Grimmie.

About 10:30 p.m. Friday, 30 minutes after her concert with the band Before You Exit at the Plaza Live ended, he walked toward the 22-year-old singer, firing several shots and triggering chaos among dozens of fans still at the venue. Grimmie fell, critically wounded, and was rushed to a hospital, where she later died.

Almost instantly, Grimmie's brother, 23, lunged at the gunman and tackled him in a struggle that ended when Loibl shot and killed himself.

Orlando Police Chief John Mina called Marcus Grimmie" a hero" and said he surely saved many lives with his quick action.

Mina said Loibl may have been a deranged fan, although the motive for the shooting was unknown. Loibl's identity was not released for several hours, giving police time to comb his home in St. Petersburg and search his computer and cellphone for any clues to the shooting attack.

The chief said Loibl did not come to the venue in his own car and had made travel arrangements to get there and to leave. He did not elaborate.

"She was doing a meet-and-greet, just signing autographs and selling merchandise," Mina said. Loibl "approached her and opened fire, striking her. We believe he came here to commit this crime," he added.

Police said they received numerous calls from people who had either witnessed the shooting or heard the gunfire.

Mina said police aren't aware of any video of the shooting.

Police Sgt. Wanda Miglio said she did not know how the shooter got inside the venue with two handguns. Mina said there were unarmed security guards at the venue, routinely checking bags and purses.

Grimmie's death set off a torrent of grief and condolences in the entertainment world, and among her fans and friends closer to her former New Jersey home.

Grimmie finished third in the 2014 Season 6 of The Voice, competing on the team of Maroon 5 front man Adam Levine.

As a teenager, she started her ascent to stardom by firing up her keyboard and recording a cover of Miley Cyrus' "Party in the U.S.A." in her Marlton bedroom - with her Sonic the Hedgehog poster taped to the wall behind her - and uploaded the performance to YouTube. Soon she amassed a huge YouTube following, gripping online viewers with powerful renditions of hit songs. Her many videos on YouTube, which were not formally marketed, have spontaneously attracted millions of views.

Just before the concert Friday, Grimmie had posted an upbeat video of herself, encouraging fans to come see her perform.

When reports of the shooting first surfaced, #PrayforChristina was the top trending hashtag on Twitter. After her death was confirmed, #RIPChristina became the top trending hashtag as Grimmie's fans took to social media to express an outpouring of grief.

The Voice paid tribute to Grimmie on its official Twitter page, saying: "There are no words. We lost a beautiful soul with an amazing voice."

Levine, her coach on The Voice, said he was "absolutely devastated and heartbroken" over the young singer's death. "Christina was a natural, a gifted talent that comes along so rarely. She was taken from us too soon."

He called the shooting "yet another senseless act of extreme violence. I am left stunned and confused how these things can conceivably continue to happen in our world."

Blake Shelton, another judge on The Voice, said he was "stunned and disgusted and heartbroken that we lost that sweet little girl."

Christina Aguilera, a judge on the show and one of Grimmie's favorite vocalists, tweeted: "My heart goes out to her family, friends & fans. XO"

Grimmie "was more than my sister," her brother posted on his Facebook page Saturday afternoon. "She was a partner in life. A superstar. A goofball. Introverted. And a friend to everyone. Genuinely."

"But above all . . . she was my baby sister. She loved the Lord and her family . . ."

Nick Gargano, 39, of Williamstown, a cousin who was in Orlando, said that Grimmie's parents flew to the central Florida city Saturday.

"She was a saint," he recalled, growing emotional. "She was the sweetest person in the world."

The singer grew up in Marlton, Burlington County. At age 5, she attended kindergarten at Bethel Baptist Christian School in Cherry Hill, where she met one of her two best friends, Sarah Luebkemann.

In a 2014 interview, Luebkemann said: "I think she knocked over my crayons or I knocked over hers. We've been best friends ever since."

Luebkemann, now 22, was grieving in her family's Marlton home Saturday after learning of Grimmie's death and didn't want to talk to anyone, her father, Bill Luebkemann, 59, said.

"It's a tragic and senseless loss," he said. "My daughter was Christina's best friend since kindergarten. We're shocked and saddened. What more can you say?"

Grimmie attended Marlton Middle and Cherokee High School through her sophomore year, when she left and moved to Los Angeles in 2012 to join Selena Gomez on tour to focus on her own singing career.

"She wouldn't hurt a fly," said Eric Parker, 22, who was her friend and fellow video-game player in middle school and high school.

"We would always tell her to sing because she had a beautiful voice," he said. "We were very proud of her - someone from Marlton on The Voice to be doing what she was doing. She was following her dream."

The spirited and enthusiastic Grimmie was grateful for the sudden fame her Voice competition inspired. She rocked a poofy, choppy hairstyle that came to be called "the Grimmie," and friends said they thought she was followed by so many because she seemed so genuine, staying true to herself.

When she and her family moved to California, Grimmie said she missed water ice, Wawa, and, most of all, the pizzas from Sal's Pizzaworks in Marlton. "Man, that is the greatest pizza ever," she told the Inquirer.

News of her death hit hard at Sal's on Saturday.

"It's absolutely heartbreaking," said Kim Rotondi, 44, a member of the family that owns the pizzeria. "We knew the whole family. I can't imagine what they're going through."

Albert Grimmie had worked at the Verizon office across the street and was a regular customer, Rotondi said.

Whenever Christina returned to the area, she went to Sal's, ordering her favorite panzerotti, a fried dough ball filled with sauce and cheese.

"She was famous, but it didn't get to her," Rotondi said. "She was still a hometown girl."

The Grimmie family had been members of Fellowship Alliance for about 10 years. Christina was last there two years ago for Easter services, taking time to pose for selfies with younger church members, said Don Hay, an assistant pastor.

"This is a time of hurt," church elder Russell said. "It seems senseless. It's a lot to wrestle with today."

"A tragedy," is what Cherokee High School in Marlton called it Saturday in a website post. "It is with heavy hearts our Cherokee family extends sincerest condolences to the family of Christina Grimmie . . . always a Chief."

Evesham Township, which includes Marlton, said in a Facebook post Saturday that "She was one of Evesham's finest."

The Philadelphia Music Alliance said in a statement that Grimmie was in Philadelphia on May 29 to perform at the Fillmore in Fishtown for Before You Exit's "All the Lights" tour.

"She was poised to be one of the Philadelphia area's next global music ambassadors, but her star shined all too briefly," PMA Board Chairman Alan Rubens said.

215-854-2592@julieshawphilly

Staff writer Julia Terruso contributed to this article, which also contains information from the Associated Press.