CROMWELL, Oklahoma - A high school teacher and coach accused of having a sexual relationship with a student turned himself into authorities. Russell Walden was arraigned Tuesday in Seminole County.

Walden was a teacher at Butner High School in Cromwell. Tuesday, he entered a not guilty plea on felony child sex and sexual battery charges for his alleged involvement with a 16-year-old student.

We've also learned that student's mother has filed a protective order against Walden.

Thirty-six-year-old Russell Walden and his attorney appeared before a judge in Seminole County. That's where prosecutors have filed three felony counts against Walden.

In court documents filed Monday, Walden is accused of kissing, touching and rubbing up against a 16-year-old girl. She goes to Butner High School in Cromwell, where Walden was a teacher and basketball coach.

Walden lived with his wife on school property. That's where the acts allegedly happened, inside their home, when no one else was there except for Walden and the 16-year-old girl.

Investigators say they exchanged explicit pictures and text messages. The alleged relationship had being going on for six months.

"These charges are extremely serious, and it's something that takes everyone's full attention," Walden's attorney, Ed Blau, said.

Over the weekend, the school board accepted Walden's resignation from Butner High School. Walden posted a $100,000 bond Tuesday.

After the arraignment, Walden's attorney said they acknowledge the seriousness of the charges, and he says his client is devastated by the allegations.

Walden's attorney also says his client does not have a prior record. His next court date is set in late February.