OMAHA, Nebraska — A former teacher who fled to Mexico with a 13-year-old student so she could have sex with him was sentenced Monday to six years in federal prison.

Kelsey Peterson was sentenced to six years in federal prison for running off to Mexico with a student.

Kelsey Peterson, 26, had pleaded guilty in July to a charge of transporting a minor across state lines to have sex and avoided a similar charge that would have carried a mandatory 10-year minimum sentence.

She will be credited for nearly one year she has served and could get another year off for good behavior, said U.S. Attorney Joe Stecher.

The guilty plea doesn’t mean Peterson is off the hook on state charges, which include kidnapping and first-degree sexual assault.

Her attorney, James Martin Davis, said he hoped those charges will be dropped, but Dawson County Attorney Elizabeth Waterman said she will proceed with a state case.

Peterson and her relatives and friends cried as they waved to each other across the courtroom and said “I love you” after the hearing.

She started having sex with the boy when he was 12 years old and a student at the middle school where she taught in the south-central Nebraska town of Lexington.

Peterson’s attorney, James Martin Davis, had publicly questioned the boy’s birth certificate. Davis said that the boy was probably at least 16 and that he was the aggressor.

Amy Peck, attorney for the boy and his family, bristled at the suggestion.

“He was a 12-year-old boy, and the defendant knew it,” Peck said in July, after Peterson’s guilty plea.

Peterson was the boy’s sixth-grade math teacher at Lexington Middle School during the 2005-06 school year and then started having sex with him in November 2006, according to court documents.

She and the boy disappeared in October, soon after the school district’s superintendent confronted Peterson about allegations of an inappropriate relationship with the boy.

Peterson was arrested a week later in Mexico after the boy called his family.

The boy was an illegal immigrant at the time but has been granted humanitarian parole by the Department of Homeland Security.

Peck has said she plans to seek a visa that could put the boy and his parents on the path to citizenship.

She said there is no relationship between Peterson and the boy.

“I would fully doubt if there will be a relationship in the future,” Peck said.