An Idaho teacher who disarmed a sixth grader after she opened fire at school earlier this month is breaking her silence for the first time.

Krista Gneiting, a math teacher at Rigby Middle School in the small town of Rigby, about 15 miles northeast of Idaho Falls, was preparing her students for their final exams on the morning of May 6 when she said she heard a gunshot from down the hall. She said she looked outside her classroom and saw the school’s janitor lying on the floor at the end of the hallway. She said she shut the door as she heard two more gunshots.

“So I just told my students, ‘We are going to leave, we’re going to run to the high school, you’re going to run hard, you’re not going to look back and now is the time to get up and go,'” Gneiting recalled during an exclusive interview with ABC News that aired Wednesday on “Good Morning America.”

A sixth grade student at the school had taken a handgun from her backpack and opened fire just before 9 a.m. local time, wounding two students and one adult, according to the Jefferson County Sheriff’s Office. The girl shot two of the victims in the hallway before moving outside and shooting the third victim, the sheriff’s office said. All three victims were expected to survive.

Gneiting told ABC News she was helping one of the students who had been shot when she saw a girl holding a gun.

“It was a little girl and my brain couldn’t quite grasp that,” she said. “I just knew when I saw that gun, I had to get the gun.”

Gneiting said she looked at the girl and quietly asked, “Are you the shooter?”

“I just walked up to her and I put my hand over her hand, I just slowly pulled the gun out of her hand and she allowed me to,” she said. “She didn’t give it to me but she didn’t fight. And then after I got the gun, I just pulled her into a hug because I thought, this little girl has a mom somewhere that doesn’t realize she’s having a breakdown and she’s hurting people.”

Gneiting said she called 911 from her cellphone as she embraced the girl, holding her until police arrived.

“After a while, the girl started talking to me and I could tell she was very unhappy,” Gneiting said. “I just kept hugging her and loving her and trying to let her know that we’re going to get through this together.”

“I do believe that my being there helped her because she calmed down,” she added.

When a police officer arrested the girl, Gneiting said she explained to her that “he needs to put you in handcuffs.”

“She didn’t respond, she just let him,” she said. “He was very gentle and very kind, and he just went ahead and took her and put her in the police car.”

The Jefferson County Prosecuting Attorney’s Office told ABC News Tuesday that the girl is “still in custody and has been charged.” It was unclear what the charges were, but Jefferson County Prosecuting Attorney Mark Taylor had earlier told reporters that the girl could face three counts of attempted murder.

The girl’s name has not been released, but the sheriff’s office said she lives in Idaho Falls.

Gneiting told ABC News she hopes people can find it in their hearts to forgive the girl and that the girl gets the support she needs.

“She is just barely starting in life and she just needs some help. Everybody makes mistakes,” she said. “I think we need to make sure we get her help and get her back into where she loves herself so that she can function in society.”

ABC News’ Kieran McGirl, Annie Ochitwa, Adriana Pratt, Dom Proto and Amy Robach contributed to this report.