Police are investigating a brazen graffiti attack on Kala­heo High School that damaged a treasured mural by the late North Shore artist Ron Artis and left several structures on the campus spray-painted with obscene writings and drawings. 

The incident apparently occurred late Saturday night, according to Kala­heo Principal Susan Hummel.

Hummel, who was alerted to the vandalism this morning by a teacher who learned about it via Facebook, said she does not think Kala­heo students were responsible.

“Graffiti is an ongoing problem for us, as it is for other schools,” Hummel said. “Sometimes it gets worse in the fourth quarter (of the school year) with all of the excitement about graduation and school pride. Whoever did this was definitely targeting Kala­heo as a school.”

The word “Kalaheo” was painted over on the school’s main entrance sign, with the word “Kailua” spray-painted beneath. “Kailua,” and “(expletive) Kala­heo,” along with several obscene drawings, were painted in pink, gold and other colors in several other areas around campus. Crosstown Kailua High School is Kala­heo’s rival.

The Artis mural, in the center of the campus, was defaced, as was a rock face on a hillside above the campus on which seniors traditionally paint the year of their graduation.

Members of the Kala­heo judo team, who were on campus for a sleepover in the school gym, saw a large group of young males on campus at about 10 p.m. Saturday. Coaches kept the team inside the gym as a precaution, but head coach Cory Ida said the trespassers left shortly after being spotted.

Hummel and a custodian arrived on campus Sunday morning to assess the damage and were soon joined by teachers, staff and students eager to undo the damage before classes resumed Monday.

“It was like, ‘Here come the troops,’” Hummel said. “As principal I can’t tell anyone to come in on a weekend, but they all volunteered to take care of it. They think of Kala­heo as ‘our school,’ and they didn’t like the idea of someone coming here and doing this.”