Every nook and cranny in the gymnasium at Glenbard North High School echoed with Gayle Dubowski's favorite hymn Wednesday night.

A chorus of 1,500 people who gathered for the graduate's memorial service belted out "Hallelujah" in perfect harmony, filling the room with their voices.

It was a fitting -- if heart-wrenching -- tribute to a 20-year-old girl whom friends, family and mentors described as a joy-filled and deeply committed Christian.

"She lived it out, simply, humbly, purely and yet boldly, said Jeff Balsom, an elder at her family's congregation, Chicago Church of Christ.

Dubowski was one of five students killed on Valentine's Day after a gunman entered a lecture hall at Northern Illinois University. Her memorial service was held at the Carol Stream school from which she'd graduated only 18 months earlier.

The stories shared by those who cared about her show a girl who was quiet, but a deep thinker. She was someone who loved wit, Bible study, her friends and her God.

But she had a mischievous side as well, like when she ran outside at recess most days in the fifth grade and was determined to smear her face with mud, lifelong friend Courtney Roy shared.

And there was her penchant for letting her instructors know they'd messed up in class with just a tilt of the head, a lopsided grin and a single, raised eyebrow.

"Usually a high school teacher can make a mistake and move right along," her former Glenbard teacher Matt Janecek said. "I did not have that luxury with Gayle."

From the level of laughter that erupted in the audience, it seemed to be a fact on which many people would agree.

Her father, Joe, told of the simultaneous grief at losing his only daughter -- the girl who kept a 15-year-old photo of a childhood dance with him in her Bible -- but peace at believing she is in a better place. She committed to following Christ when she was baptized June 6, 2003, and never looked back, he said.

"Because of the way she lived her life from that day forward, we have confidence she did not die that day," he said.

"I believe God took her home," he continued, "to spare her from the pain and suffering because of the evil that is in this world."

The many friends she left behind made sure the music she loved so much, and the singing she cherished, captured her beliefs throughout the two-hour service remembering her life.