Mike Africa Jr., the son of two MOVE members imprisoned for the death of a police officer during a 1978 Philadelphia police raid, spent decades trying to free his parents, a struggle depicted in the documentary “40 Years a Prisoner.” “When I learned that they were actually in prison, I might have been 13 years old, I started looking for something that would show their innocence,” says Africa Jr. “I wound up doing that for over 25 years.” The documentary will debut on Tuesday, Dec. 8 on HBO and HBO MAX. “40 years a Prisoner” was an official selection and special presentation of the 2020 Toronto International Film Festival. “40 Years a Prisoner” chronicles the 1978 Philadelphia police raid on the radical back-to-nature group MOVE and the aftermath that led to a son’s decades-long fight to free his parents. The documentary illuminates the story of a city grappling with racial tension and police brutality with alarming topicality and modern-day relevance.