Christopher Thunborg was found not guilty
by a 4th District Court jury of second-degree felony child abuse homicide for the March 11, 2008, death of 13-month-old Austin Pettersson, said Utah County Attorney Jeff Buhman.
However, Thunborg was found guilty of obstructing justice
, a third-degree felony. He faces up to five years in prison when he is sentenced by Judge David Mortensen.
Thunborg took the witness stand this week and denied intentionally harming the child. He did, however, describe an accidental fall with the boy.
Thunborg -- who was watching the boy for his girlfriend, 19-year-old Whitney Pettersson -- testified that the child was in his arms when he stepped on a puppy, fell to the floor and landed on top of the boy
"It seemed like he got the wind knocked out of him," Thunborg said, adding that the boy stopped crying as soon as he saw his bottle.
Thunborg testified that he thought no more about the fall until he was being interviewed by police, following Austin's death.
An autopsy revealed what the medical examiner called the likely cause of death -- a laceration on the boy's small intestine and a tear in his stomach -- caused by blunt-force trauma to the abdomen.