SOUTH PORTLAND (NEWS CENTER Maine) -- South Portland police have arrested a South Portland High School student accused of making a threat against the school.

Police said they were alerted by students to a Snapchat message in which a classmate wrote about "shooting up the school." Coordinating with school staff, police located the 15-year-old boy accused of writing the message before he arrived at school on Thursday morning.

RELATED: Kids that saw something, said something praised by So. Portland officials

NEWS CENTER Maine is choosing not to identify the student because he is a juvenile.

Law enforcement confronted the student in the parking lot of the South Portland Community Center as he walked to school, and searched him for weapons. A knife was found, but no firearms, according to police. He was arrested on charges of terrorizing and carrying a concealed weapon.

Police said the boy had never previously given them trouble. They decided after consulting with juvenile corrections officials to place him under house arrest. His name was not released.

"It's 2018," said Lt. Frank Clark, "so we really need to take these sort of events seriously, and we here at the police department do. We've changed our protocols over the years to respond to serious threats against our schools and other businesses and whatnot in the city."

Lt. Clark added police are asking members of the community to do the same.

"We can't make assumptions anymore that because somebody said something, and decided that they didn't want to say that or they tried to retract it, that it's not going to happen. We need to validate that information. We need to look into it and investigate it, and that's what we're here for."

South Portland School Superintendent Ken Kunin sent an email to parents regarding the situation Thursday morning:

Dear South Portland Schools Families,

I am writing to alert you to a situation involving the high school. We have learned that a student made threats on social media regarding the high school. Other students who saw this did the right thing – if you see something then say something – and the student involved was apprehended this morning before entering school. He had no firearms in his possession when apprehended and there is no imminent threat to the school.

The student is now in police custody and we anticipate will face serious charges. At the same time, we will follow our disciplinary process. At all times we will strive to maintain a safe environment for all of our students, our staff and our community. We greatly value our partnership with the South Portland Police and with our entire community to ensure the safety for our students.

Thank you,

Ken Kunin.'

Max Culkins, a student at South Portland High School, praised school officials for their swift action.

"I mean, you know high school kids," he said. "They do anything to be surrounded by attention. Everyone was a little bit scared, everyone was a little bit shook, but we're all just walking around and everyone was talking about it. But I'm just glad that it's over. I feel a lot safer here. I feel that the teachers handled it pretty well."

The arrest on Thursday morning happened amid high tension across the country after a school shooting in which 17 people were killed Wednesday in Parkland, Florida.