LAKE FOREST, Ill. (CBS) –- A Lake Forest middle school principal who “sexted” a college student resigned Sunday, but some parents demanded the departure of the district’s superintendent, too.

Deer Path Middle School Principal John Steinert in 2009 pleaded guilty to harassment by electronic media, after sending dozens of unwanted and sexually explicit texts, messages and photos of himself to a 22-year-old Lake Forest Police Department intern. The messages were sent on a school cell phone.

After an investigation by Superintendent Harry Griffith, Steinert stayed put as principal until the true nature of the messages came to light last week in The Chicago Tribune and other media outlets.

Reports last week said Steinert sent the woman a picture of his penis, and left voice mails and texts that suggested sex acts he wanted to perform with her and asked her about pornography and sex toys.

Steinert persisted even after the woman told him she was not interested and asked him to leave her alone, and she finally contacted police in Gurnee, where she lived, reports last week said.

Parents expressed anger Sunday night that Steinert was allowed to stay. The Lake Forest School District 67 board gathered for a hastily convened meeting and accepted the principal’s resignation.

“I’m embarrassed to call you my school board members,” parent Michael Beacham said.

“Either there’s been gross incompetence or there’s been a cover-up. In either case, it’s just unacceptable,” he told reporters.

Griffith said he won’t resign. He says initially he only saw a redacted version of the police report.

Previously, “we had information that this was about texting between two adults,” Griffith told reporters. “When we actually saw the real material was just three days ago, we realized it was more about sexting, and that was heinous behavior.”

School board members say they still have to discuss details surrounding the controversy. A meeting between parents and the school board was scheduled for 5 p.m. Monday.