Teacher Nabbed After Fleeing With Student Caught in Mexico, she was having affair with 13-year-old, police say By Nick McMaster, Newser Staff Posted Nov 3, 2007 12:14 PM CDT 0 comments Comments Kelsey Peterson in an undated file photo. (AP) (Newser) – A 25-year-old female math teacher who allegedly ran off to Mexico with a 13-year-old former student was arrested today, the AP reports. The boy has been turned over to his relatives. The two, who met when she taught him sixth-grade math at a Nebraska middle school, headed for the border when police began investigating a romantic affair between them, authorities say. Teacher Kelsey Peterson, 25, is in FBI custody and faces federal charges including transporting a minor across state lines for sexual activity. Mexican authorities caught them after Peterson's license plate was photographed at the border. Police have recovered several emails and letters in which the couple professed their love for each other.