LAWRENCE JOYNES began teaching in Montgomery County Schools in 1985, spending most of the past decade teaching music at New Hampshire Estates, an elementary school in Silver Spring. By all accounts, Mr. Joynes was beloved. As The Post reported in April, many parents said their children considered him “funny and engaging, with a classroom of toys and instruments.” Little did these parents know that this same man, in this same classroom, was secretly — and, as it turns out, not-so-secretly — collecting pictures of their young daughters for use in child pornography videos.

Would that those pictures were the extent of this disgusting circumstance. When Mr. Joynes was arrested in February, apprehended by police while attempting to escape through his house’s back door, far more harrowing details began to emerge little by little.

The Baltimore and Montgomery county police departments have since uncovered a mass of other images and video files Mr. Joynes collected, and the former music teacher confessed to investigators that he would play “games” with his students that entailed sticking peppermint sticks into their mouths in apparent simulations of sex acts.

This week, however, the full extent of this sickening story became clear. According to court documents, Mr. Joynes has been charged with sexually abusing no fewer than 14 students in the past eight years and with the second-degree rape of a girl younger than 15, whom he sexually abused for as long as two years in the early 1990s, police say.

Among the most chilling facts The Post reported is the inscription Mr. Joynes left in that same girl’s 1992-93 Eastern Middle School Yearbook. “Always remember that I love you,” he wrote. “You are my reason for going on. We’ll be in touch over the summer. Be mine always. Your Pookins Bear.”

As unsettling as those details are, however, even more shocking is that many people turned a blind eye to Mr. Joynes’s behavior over the years, even after complaints were filed. One teacher who worked with Mr. Joynes told The Post that she’d reported him to school administrators twice, including when he allegedly locked the door to his classroom after he’d invited three first-grade girls for lunch. At least one victim continued to be abused after that and other reports were made.

In a statement, a spokesman for Montgomery County Schools said that the school district was “looking into how these allegations were handled by our staff,” with the aim of developing a new protocol for handling allegations of inappropriate behavior. That investigation must honestly answer the glaring question of how it was possible for officials to ignore alarm bells for so long. Whatever protocol is established should ensure that will never be the case again.