(Bonnie Jo Mount/The Washington Post)

School officials in suburban Maryland are investigating an incident involving a swastika found drawn on a wall in a boys’ restroom.

The discovery Wednesday at Silver Creek Middle School in Montgomery County came as the latest of more than 20 hate incidents in Maryland’s largest school system during the 2018-2019 school year, officials said.

It was reported to police and school system administrators, according to a letter sent to parents at the school. Building services staff removed the symbol, etched in pencil.

“Our children need to understand that certain images, words, and actions, regardless of intention, are hurtful, inappropriate, and disrespectful,” Principal Traci Townsend said in the letter. “We are very saddened by this incident.”

Disciplinary consequences will be imposed if the offender is identified, she said. “This behavior is unacceptable and will not be tolerated,” she said.

As the school year winds down, Montgomery County officials said the sprawling school system, with 206 schools, has seen fewer acts of bias — involving race, ethnicity, religion, gender identity and sexual orientation — than in the previous school year.

Last year, there were 56 incidents, according to a school system report on serious incidents.

But this school year, some acts of hate were highly public.

At Richard Montgomery High School in Rockville, red cups that had been arranged in fencing to spell the word “seniors” were rearranged to spell out the n-word in late December, according to a school letter. A few weeks later, a bright orange swastika was spray-painted on the school.

More recently, two students at Walt Whitman High School in Bethesda posted an image of themselves in blackface on social media and used the n-word as they described it. The incident drew condemnation from county officials.

School Superintendent Jack R. Smith released a video message on the issue Wednesday evening.

“Recent hateful and bigoted incidents in our school community remind us that we still have work to do,” he said. “I want to be clear, there is no room for hate in Montgomery County Public Schools.”

In 2016-2017, there were more than three dozen bias incidents that were reported by or took place at Montgomery County schools, mostly involving vandalism with swastikas, racial epithets or other bigoted messages, according to an analysis by The Washington Post.