(Chicago, IL) -- A woman from Portland is accused of cheating in the Chicago Marathon. Twenty-eight-year-old Emily Clark finished the October 13th race with a time of 3 hours and 59 minutes-- under the average marathon finish time for a woman in the U.S. A blog that investigates runners says Clark's pace changed suspiciously at the halfway point. Clark was previously disqualified from the PeaceHealth Apple Tree Half Marathon in Vancouver for allegedly riding a bicycle for part of the race. She has confessed to cheated in five previous races, including the Chicago Marathon in 2013.