Souix Falls, SD (Learfield Wire Services) -- A South Dakota man will spend the rest of his life in prison for the murder of Vikings running back Adrian Peterson’s son.

Joseph Patterson of Sioux Falls was convicted in September of second-degree murder, first-degree manslaughter and aggravated battery back in the death of his girlfiend's two-year-old son Tyrese Ruffin. Peterson found out only shortly before the boy's death that Tyrese was his son.

Ruffin continued to maintain his innocence at the sentencing hearing, claiming all he did “was try to help.” The medical examiner ruled that the toddler was killed by four blows to the head. Defense lawyers claimed Ruffin choked on a fruit snack.

(Learfield Wire Services)