When the students arrived the next morning the group was overwhelmed by their reaction. Many of the notes stayed on the lockers for days and others wore them on their shirts.
So shocked were they by a classmate taking his own life, that these students decided they needed to do something.
Both staff and students were devastated when they heard about the death of Kwadwo Boateng at the US school.
Says student Erica English: '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.'
Erica and her friends wanted to mourn their classmate in a positive way so they decided to stick brightly-coloured Post-it notes with an encouraging message on everyone's locker.
Trouble was, the school has 3,600 students.
They got permission from the principal to stay after school and spent hours posting the notes on every student's locker. They also wrote notes for the teachers.
Says Erica: 'We wanted things that would hit people hard and make them realise that they matter and are important.'