A former Nebraska teacher who fled to Mexico with a 13-year-old student has been sentenced to eight to 10 years in prison.

Kelsey Peterson's sentence Thursday in Dawson County District Court comes after she pleaded guilty in January to two counts of first-degree sexual assault of a minor.

Her sentence is to be served simultaneously with a six-year federal prison sentence she's already serving for transporting a minor across state lines to have sex.

She had faced up to 50 years in prison on each count.

Authorities say 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.

They fled to Mexico in October 2007.