Last Friday, Fair Haven Union High School made headlines when Jack Sawyer, 18, was arrested and charged with plotting to kill students and staff. A plot that was foiled thanks in part to Angela McDevitt.

"I definitely right away knew I had to say something," McDevitt said.

The high school junior from Poughkeepsie, New York, knew Sawyer from when they attended the same school in Maine. And when she got disturbing texts from him earlier this month referencing the school shooting in Florida, she said her gut told her this wasn't just for attention.

"That's not something that you would joke about right after that. And just the insensitivity of it, that made me think that 'this is serious,'" McDevitt said. "At first I was like, 'Who do I go to about this?' Like, I don't want to walk into the police station."

After talking with her friends, she went to her school guidance counselor the next day.

"I was very emotional," she said. "He first took care of my emotional needs and made sure that I wasn't sitting in a room alone. And then he took my phone."

On the phone were the text messages between her and Sawyer. Those gave police enough cause to go back to Sawyer and arrest him. His later conversations with police revealed his alleged plan to shoot up Fair Haven Union High School.

McDevitt said she felt sick hearing the reports.

"It was just hard to hear because, again, it's like you think you know someone," she said.

Her actions are drawing praise from Vermont officials, including the governor.

"By the grace of God and the courage of a young woman, we averted a horrific outcome," Gov. Phil Scott, R-Vermont, said after Sawyer's arrest.

Reporter Cat Viglienzoni: How did it feel afterward when you heard people reacting to what you did?

Angela McDevitt: At first I was like, I definitely think they're forgetting that I knew this person. And I was like, I don't want to be thanked, I feel like crap... OK, potentially I saved many lives of people that I didn't know. But I also lost someone who I thought I knew.

But she said she wants other students to know while it's hard to do, if you see something, you have to say something.

"I kind of thought, 'What am I going to feel more guilty about-- if I betray this friendship or let people potentially die?' And the answer was pretty clear to me," McDevitt said. "In this scenario, the friendship isn't the most important thing."

She also wants her peers to know that if their friends are showing warning signs, it's up to them to report it. But they're not alone.

"Know that you can't fix everyone yourself," she said. "And sometimes you do need to ask for outside help."

We asked McDevitt what schools could do to make students more comfortable with reporting concerning behavior. She said having students establish a relationship with their counselors early on would help them if they ever find themselves in her position.