On the 12th anniversary of the terror attacks of Sept. 11, 2001, Santa Margarita Catholic teachers and students arrived on campus to find their school had been vandalized.
Lockers weren't tagged with spray paint but with Post-It Notes, each one with an inspirational, encouraging or personal message handwritten on it.
Those responsible were unknown to the school's staff, which really wanted to know who had been busy while the campus was empty.
The culprits were eventually found by sheer coincidence, according to Jaimee Lieske in the communications department.
Sophomores Emerica Rogers, 15, and Bella Montes, 16, were walking together when they were stopped by Amanda Coronado, the school's director of communications.
Eager to find out who was responsible for the "sea of yellow," as she described it, Coronado was on campus taking photos of the the Club Fair and asked the two passing girls if they knew who had surprised everyone in school.
The girls laughed.
It was them.
"The girls wanted to do something that would allow them to bring positivity to their school community," Lieske said. "They figured everyone could use a word of encouragement and, even if it helped only one person get through their day, that would be enough for them.
"Also, with it being 9/11, they thought it would be a nice way to lift everyone's spirits."