Last year, judge John Hodge found Jordan Brown delinquent -- the juvenile court equivalent of guilty -- of the 2009 fatal shooting of his father's fiancee, Kenzie Marie Houk, 26, when Brown was 11, the Pittsburgh Post-Gazette reported.
However, on Wednesday, the state Superior Court vacated the decision, saying Hodge's ruling was "clearly contrary to the evidence."
The appeals court said prosecutors had not proven Brown and Houk's two daughters were the only people in the house at the time of the shooting and that Hodge based his ruling on testimony from a tree-cutter who said he saw only the kids' footprints in fresh snow on the driveway.
"The juvenile court appears to have mistakenly concluded that no footprints existed based upon the absence of any testimony regarding the condition of the snow," the ruling states.
Dennis Elisco, Brown's attorney, said he and his colleagues are "trying to figure out what our options are" and whether a retrial will be scheduled.
Meanwhile, Houk's mother, Deb Houk, said her family is "definitely upset."
"I'm tired of it, all of it," she said. "He did it. And now I've got a daughter buried at 26 and a baby buried with her."