Raleigh, N.C. — A Raleigh elementary school is urging parents to talk to their children after learning a former PE teacher convicted of child sex offenses involving two students might have victimized even more.

John Peter Skatrud, 43, who taught at Yates Mill Elementary School from August 2008 to February 2010, is serving 11 to 17 years in prison after pleading guilty in August to four counts of indecent liberties with a minor and five counts of second-degree sexual exploitation of a minor.

The convictions stem from inappropriate touching and photos that Skatrud took of two 8-year-old girls.

Cris Mulder, a spokeswoman for the Wake County Public School System, said the school had been working with the Wake County District Attorney's Office and the State Bureau of Investigation when it learned that there were additional photos of more students.

The families of three students have been notified, she said, but there were other photos in which children couldn't be identified.

"The school system wants to do everything it possibly can to ensure that any student who was inappropriately photographed by Mr. Skatrud receives the available information and appropriate support," Yates Mill Elementary Principal Ann Marie Johnson wrote in a letter to be sent to parents Wednesday afternoon.

"We are providing this information to you so that you can carefully consider whether you want to discuss this situation with your child to determine whether he/she may have been photographed in an inappropriate manner or otherwise treated inappropriately by Mr. Skatrud during the time he was at Yates Mill," Johnson continued. "It is our hope that this can be done in a manner that will not cause any alarm to your child if none is warranted."

Melanie Shekita, the assistant district attorney prosecuting the case, was unavailable for comment Wednesday, but Wake County District Attorney Colon Willoughby said it is not unusual for investigators to continue looking into a case like Skatrud's after someone has been convicted.

"We really think it's important to report if they believe crimes have occurred and allow law enforcement to come in and investigate that," Willoughby said. "Once a perpetrator is incarcerated, it gives them a sense of courage that they are willing to come forward when perhaps before they wouldn't."

During Skatrud's sentencing, Shekita said the school had "come to love" him and that he had gotten very close to the victims' families, even driving the girls home from school on many occasions.

"It was easy for him to garner the trust of young children," she said.

Skatrud also coached volleyball at North Carolina State University and for the Capital City Volleyball Club.He also worked at Sanderson High School from February 2004 to June 2008, a Wake County schools spokesman said.