A Lookingglass man accused of killing his girlfriend’s 2-year-old son in 2011 went on trial for murder today. Mark Allen Vanderhoof, 52, is accused of killing Dennis Young, whose mother, Brianna Snow, he was dating at the time. Vanderhoof was initially arrested on suspicion of first-degree assault, but the charge was increased to murder. He’s been in Douglas County Jail since his arrest in January 2011. Last July, he waived his right to a jury trial. Instead, Douglas County Circuit Judge Ronald Poole will hand down the verdict. Vanderhoof is represented by Medford attorney Don Scales. According to the indictment, …