A book with “concerning illustrations” of sex acts has sparked a police investigation, school walkout, and response from Massachusetts Gov. Maura Healey in support of “inclusive, comprehensive resources.”

The ordeal started with a Dec. 8 complaint to the Great Barrington Police regarding Gender Queer: A Memoir by Maia Kobabe, which a teacher at W.E.B. Du Bois Regional Middle School made available to her eighth-grade students.

The 2019 book, the most frequently challenged title in the country in recent years, contains graphic illustrations of gay sex, sex toys, sexting, “transgender magic,” masturbation and other topics.

“Because this complaint was made directly to the police department, we are obligated and have a duty to examine the complaint further,” police chief Paul Storti told Boston.com.

Police officials consulted with school leaders before sending a plainclothes officer to investigate at the end of the day, he said.

“After a brief conversation with the teacher, the officer was advised that the book in question was not there and could not be accounted for at that time,” Storti said.

“The interaction with the teacher was cordial,” Storti told WGBH, adding that the officer was unfamiliar with the book before the complaint.

“The officer didn’t touch anything. They didn’t search,” he said. “They basically asked if the book was still there, to give the context of what we were dealing with. The teacher said the book wasn’t there, and the officer left.”

Julia Sabourin, a spokesperson for the Berkshire County District Attorney, confirmed to WGBH that police were required to investigate the complaint.

“Police are duty bound to investigate reported criminal acts, and they can’t choose when to respond and when not to,” Sabourin said. “’Gender Queer’ is the most banned book this year … but just researching (that context) doesn’t complete what officers are bound to do.”

Middle school Principal Miles Wheat told Boston.com that Gender Queer is not part of the school’s curriculum, but rather part of a teacher’s classroom collection.

An investigator followed up by notifying the district attorney, a common procedure in sensitive cases, before determining it was “a matter to be managed within the Berkshire Hills Regional School District,” according to the news site.

The incident prompted the school committee and Superintendent Peter Dillion to issue an apology to the school community on Tuesday, according to The Berkshire Eagle.

“The recent incident at the middle school has challenged and impacted our community,” the statement read. “Faced with an unprecedented police investigation of what should be a purely educational issue, we tried our best to serve the interests of students, families, teachers, and staff.

“In hindsight, we would have approached that moment differently. We are sorry,” it continued. “We can do better to refine and support our existing policies. We are committed to supporting all our students, particularly vulnerable populations.”

The debacle also prompted more than 100 students and staff at Monument Mountain Regional High School to stage a walkout on Friday to protest.

Wheat told Boston.com “there have been a variety of reactions from the school community.

“The most common reaction that I am seeing is concern that this seems like censorship and people are very uncomfortable with that,” he said.

Gov. Maura Healey is among the concerned, issuing a statement declaring “book banning has no place in Massachusetts.”

“Our administration stands with educators who are committed to ensuring that their students have inclusive, comprehensive resources,” Healey wrote. “I’m proud to see these students stepping up to support their teacher, their peers and an inclusive learning environment.”

The ACLU is also weighing in, both about the obscene material and a body camera worn by the police officer who visited the eighth-grade classroom. The human rights group has filed public information requests for information about the incident.

“That’s partly what is so concerning,” Ruth Bourquin, attorney for the ACLU of Massachusetts, told the Eagle. “Police going into schools and searching for books is the sort of thing you hear about in communist China and Russia. What are we doing?”

In Massachusetts, material is considered obscenity if it’s of sexual interest, describes sexual conduct “that is patently offensive to an average citizen,” and “has no serious value of a literary, artistic, political or scientific kind,” according to the news site.

“It’s about the freedom to read,” Du Bois Librarian Jennifer Guerin told the Eagle. “It’s about providing voluntary access to a well-written, highly acclaimed resource in a safe place for a teenager who might want or need it.”

District officials are now inviting the community to learn more about what happened and offer their feedback at a Jan. 11 school committee meeting.

“We want to clearly and unequivocally state that the school district does not support banning books,” a statement read. “Also, we are committed to ensuring that all students feel safe as we support an inclusive environment at our schools.”