Julie Hong

El Centro, California (KPTM) - Kelsey Peterson is now formally charged for running off with one of her former students, a boy who is only 13-years old.

Peterson and the teen were arrested three days ago in Mexico on a federal warrant. Wearing a red prison issued jumpsuit, her jaw clenched, a Central Nebraska teacher said nothing in a federal California court Monday afternoon.

She faces federal charges of transporting a minor to engage in illegal sexual activity.

The U.S. Attorney for Nebraska says it could be ten days to three weeks before Peterson is brought back here to Nebraska.

Not only does she face a single federal charge she faces a number of counts in Dawson County.

 Inside the California federal courthouse, Kelsey Peterson showed little emotion as she faced charges for running away with one of her former 13-year-old students.

She was appointed a federal public defender for now, but federal prosecutors want her back in Nebraska. U.S. Attorney for Nebraska, Joe Stecher says, "arrangements will be made for her transportation here to be formally arraigned in Nebraska."

The weeklong search for Peterson ended Friday night but prosecution against the 25-year-old is far from over.

In addition to the federal charge, Peterson could face more charges in Dawson County, including kidnapping and child abuse.

"I'll be reviewing the case again to determine additional charges which are likely and whether or not any other amendments need to be made to the charges," says Dawson County Attorney Liz Waterman.

California police say the pair agreed to leave Nebraska after their sexual relationship became public.

Stecher says a minor cannot give consent. "He is a victim. He's a child and she is an adult and there's no doubt about it, he is a victim."

Once Peterson returns to Nebraska, Stecher says he will work with state and county prosecutors. "The investigation is still unfolding and depending on what comes from the final evidence we have Liz Waterman and myself will sit down and determine which venue would be more appropriate to prosecute," says Stecher.

Peterson's next court appearance will be in California on November 7th. She also has a combined hearing set for later in the month to verify who she is and to decide if there's enough evidence to move the case to trial.

On the federal charge alone, it carries a minimum of ten years to life because it's considered a sex crime.

The 13-year-old boy is in Mexico with family members there. It's unclear right now if he will be brought back to Nebraska. Stecher says the boy's family wants him back in Nebraska.

The teen is a Mexican National. Stecher says his office is working with the Mexican government and immigration officials to see if they feel it's necessary for him to return.

An immigration attorney Fox 42 spoke with says if he's allowed, it would likely be on what's called humanitarian parole. "It would require quite a bit of cooperation and documentation that he would be needed in the case against the defendant in this instance," says immigration attorney Amy Peck.

One uncle says the Lexington student is staying in his family's hometown in southern Mexico with his grandmother, uncles and father.