When one of their friends took his own life, classmates posted inspirational messages of hope on lockers.

Students at a US high school were shocked and devastated to hear that one of their peers, a popular 15-year-old, had taken his own life.

Both students and teachers were stunned when they heard about the death of Kwadwo Boateng.

"He was always happy and smiling. He was really funny and always cracking jokes. Everyone loved him," classmate Erica English told TODAY parents.

Facebook/Mason City Schools From left to right, Anna Aronson, Jessica Morse, Erica English, Ellie Uematsu, and Michelle Crispin picture with some of the Post-it notes they left for grieving students.

She continues: "No one ever expected this to happen. It was shocking to everyone in the whole school. At first, I couldn't believe what I was hearing. Everyone was sad and you could tell when people walked down the halls that it hit them really hard."

Wanting to do something to support their grieving school, a group of six sophomore students; Anna Aronson, Michelle Crispin, Erica English, Nick Krueger, Ellie Uematsu and Jessica Morse, put their heads together and came up with a plan that would help students to mourn Boateng in a positive way.

Anna Aronson suggested that the group write words of encouragement on brightly coloured Post-it notes and stick them to every locker in the school. It wasn't going to be easy though, the school has around 3,600 students.

Facebook/Mason City Schools The halls of Mason High School in Ohio after a group of their students spent hours sticking up Post-it notes.

But determined to carry out their idea they pressed on, getting permission from the principal.

"We wanted the messages to be personal so we wrote, 'You are' and then we came up with a bunch of words that we thought would be good, things that we wanted everyone to know were true," Aronson explains.

English added: "We wanted things that would hit people hard and make them realize that they matter and are important."

Facebook/Mason City Schools Students post inspiring Post-it notes on school lockers and teachers' doors after losing a peer to suicide.

The dedicated group split the cost of the post-it notes between them and began writing the messages of support. After they'd been given permission to go ahead with the plan they arranged for the school to be kept open after classes finished for the day.

The friends gathered at 2.15pm and worked tirelessly until nearly 10pm, making sure that every student had a note.

"When it started to get late, we got a little worried about getting it all done. But we wanted to commit to the project and stay as long as needed to make sure everyone got what they deserved," Crispin says.

"One of the things that inspired us to do this was that Kwadwo was such a positive person. He always wanted to spread so much joy and make people happy and we really looked up to him for that. We just wanted to do what he would have done for the world."

The six students also knew that their teachers were grieving and so left special messages on the hundreds of teachers' doors too.

"We wrote things like 'We appreciate you', 'we look up to you', 'we love you' and other messages that spoke for all the Mason High School students," explains Morse.

It may have taken until 10pm.. But seeing everyone's face was worth it! I'm glad we got to put these up ily all :)) pic.twitter.com/Tp0eu1R1u9 — Anna Aronson (@anna_aronson233) August 31, 2016

When students arrived at school the following morning, the group was overwhelmed with the reaction they received from classmates and teachers.

"When I walked in everyone was smiling and reading their Post-it notes and comparing them with other people," Aronson says.

"You would see people walking around the school with their note taped to their shirt."

Many of the notes stayed on the front of lockers for days. "I think there [has been] a lingering impact. Some people really took this to heart and I know that all of the things we wrote on the notes are true. They are loved and they are not alone," says Krueger.

"There was a kid in my chemistry class and I noticed he had the Post-it note that said 'You are Magnificent' on his shirt," Uematsu said.

"Seeing that left a big impact on me. I think I made his day and that is all we wanted to do."

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