SAN DIEGO -- A 26-year-old former teacher's aide at a Carlsbad elementary school accused of using the Internet to exchange sexually explicit pictures and videos with a 13-year-old girl in Michigan was indicted on federal child exploitation charges, federal prosecutors announced Friday.

Michael N. Runnestrand, 26, faces charges of sexual exploitation of children, receipt of child pornography and transferring obscene material to a minor.

The indictment alleges that Runnestrand persuaded the girl to make sexually explicit videos and photos of herself in Michigan and send them to him in California.

Runnestrand is also accused of sending the girl images of himself masturbating, according to the indictment.

"Today's charges, involving the production of child pornography through sexually abusing a minor are quite serious," said U.S. Attorney Stephen J. Murphy of the Eastern District of Michigan. "The conduct allegedly included both production and receipt of several images of child pornography and involved a breach of the trust parents and students place in their teachers."

According to an affidavit in support of the indictment, the girl met Runnestrand when she was 11 years old at Calavera Hills Elementary School in Carlsbad, where he was a teacher's aide for her sixth-grade class.

The girl and her family moved to Michigan in July 2004, and she and Runnestrand began texting each other.

The girl told authorities that the defendant asked her for some pictures of herself, including some in her underwear with her hand down the front of her panties, which she did.

In December 2005, the girl said she and the defendant started having "computer sex," stating it was Runnestrand's idea.

In April 2006, the girl went back to California to visit a friend and Runnestrand asked her to go to Disneyland, but her mother said no, according to the affidavit.

The mother did agree, however, to let her daughter see Runnestrand at the friend's house as long as her friend's mother was there. At one point during Runnestrand's visit to the friend's home, he put his hand down the girl's pants and touched her vaginal area over her underwear, the affidavit stated.

As part of the case, a detective from Oakland County, Michigan, examined the girl's computer and found files of her masturbating, according to the affidavit.

In December 2006, a police officer in Oakland County assumed the online ID used by the girl and during an online chat session mentioned an explicit video of Runnestrand on the girl's computer. The defendant allegedly responded, "Oh wow, that's going to be the death of me. Delete it," according to the affidavit.

In another chat, the officer posing as the girl asked Runnestrand what he wanted for Valentine's Day, and he said he wanted the girl to destroy the videotape he sent to her, according to the affidavit.

When Runnestrand requested a picture of the girl, and the officer told him he should have kept previously sent photos, the defendant responded, "No way, if someone looked on my computer ... game over," according to the affidavit.

If convicted on the production of child pornography charges, Runnestrand faces 15 to 30 years in federal prison, prosecutors said. The defendant also faces between five and 20 years in custody if convicted on the receipt of child porn charges, and up to 10 years in prison if convicted on the transferring obscene material to a minor charge.