Where these students were sitting seems to have made the difference between life and death; those killed were in or near the front row...
The family of one student who was shot in the hand said she switched seats with fellow student Dan Parmenter to chat with her girlfriend. Parmenter died in the shooting.
His desk at the campus newspaper became a symbol of the school's grief.
The sophomore finance student graduated from York Community High School two years ago.
Moments before he was killed he had lunch with Tom Salzman.
"One of the most overall genuine people I have ever met, always had a smile on his face," he said.
Gayle Dubowski was a sophomore and a graduate of Glenbard North High School, where she sang in the choir.
She was described as a good person with a big heart.
"Many of our teachers had Gayle in class, and she was a very positive girl, a very intelligent girl, one of our top students," said John Mensik, Glenbard North High School principal.
Ryanne Mace, 19, was a sophomore who wanted to become a psychologist. Her last posting on Facebook Thursday said "Happy Valentine's Day everybody." She was an only child.
Catalina Garcia, 20, was the youngest of four siblings. She attended NIU to follow in her brother Jaime's footsteps.
She had just talked to her family on Tuesday, and she was looking forward to coming home this weekend to celebrate her mother's birthday.
Julia Gahant was the oldest at 32, she too wanted to become a teacher.
In a Christmas card last December, she wrote "I have four more semesters until I'm qualified to teach second graders."
Her career in the military took her from Bosnia to Japan and Korea. When she left the military for college, her family thought that would keep her out of harm's way.
Her fiancee was killed in a car accident four years ago. Her family believes they are together again.
"This was a sign from Julie to let us all know that she is happy, that she is with (fiancée) Steve, watching over us. That's all she wanted," said cousin Chastity Schafer, crying.
"She was just loved by everybody. I'm going to miss her very much," said sister Jennifer Latchford in tears.
There has been an outpouring of support for the victims' families. Several organizations have offered to pay for funeral arrangements. So far, no arrangements have been made.