A Harrison High School English teacher was arrested Wednesday on computer pornography charges for reportedly text-messaging a 15-year-old student to solicit sex and transmitting cellphone photographs of his genitalia to the her.

Christopher Michael Nicklis, 36, of Kennesaw, has resigned his teaching job and was released from the Cobb County jail on $15,000 bond Thursday afternoon.

One of the text messages was sent at midnight Nov. 1 from Nicklis’s cellphone, according to a police incident report.

The investigation began after the girl’s mother found the text messages on her daughter’s phone and reported the activity to school officials, police said.

Nicklis served as yearbook adviser and journalism instructor at the school, where he taught for three years, according to the west Cobb school’s Web site. He previously worked as a teacher and newspaper advisor at Lassiter High School in east Cobb. Before coming to Georgia, Nicklis taught for three years in South Carolina and is a graduate of The Citadel.

He is the third Cobb teacher — and the second teacher at Harrison — to be charged with sexual misconduct involving a student in the last year.

Harrison orchestra teacher Steven Parkman was indicted in November of sexual assault charges against a former student. He filed a motion last month to have those charges dismissed because he claimed the sexual contact was consensual.

Last month, Pebblebrook teacher Corey L. Grayson was charged with enticing a child for sex after reportedly writing a 15-year-old student a sexually suggestive note.

Parkman and Grayson immediately resigned their positions.