EASTON, Pa. (AP) - A man who was 17 at the time of the shooting death of another teenager in what authorities called a case of mistaken identity a decade ago has won a new trial.

A Northampton County judge on Wednesday vacated the guilty plea of Paul Serrano III, 27, to first-degree murder and the life-without-parole sentence in the slaying of 15-year-old Kevin Muzila, of Bethlehem, a week before Christmas in 2006.Judge Emil Giordano ruled that the plea wasn't knowing and voluntary, given that he entered into it in exchange for prosecutors withdrawing efforts to seek the death penalty.Defense attorney Matthew Deschler said his client was 18 when he pleaded guilty but only 17 at the time of the crime and therefore was ineligible for the death penalty under a ruling by the U.S. Supreme Court."It was overlooked," said District Attorney John Morganelli, who handled Serrano's case. "It was overlooked by everyone."Serrano had also challenged his life sentence, citing a later Supreme Court ruling barring automatic life terms without parole for juveniles.Prosecutors said another man had ordered the death of a rival drug dealer, but Serrano went to the wrong apartment and opened fire, killing Muzila.Morganelli said he offered Serrano a plea deal recommending a sentence of 30 years to life, but Serrano rejected it. With the case now scheduled for trial Feb. 27, that deal is off the table, he said.Morganelli, who plans to handle the case himself, said he has a confession and witnesses lined up to testify, he believes the defendant "is making a very huge mistake" in going to trial.