SALT LAKE CITY (AP) — The oldest son of a Utah doctor smiled as he shook hands and hugged friends and family after his father was sentenced Wednesday to 15 years to life in the killing of his ex-wife and escorted out of court in handcuffs. The sentencing of John Brickman Wall closed another chapter in a long, painful journey of 21-year-old Pelle Wall, who was instrumental in pushing police to investigate his father even after the 2011 death of his mother, university cancer researcher Uta von Schwedler, was initially ruled a suicide. Pelle Wall spoke during the sentencing hearing, asking state Judge James Blanch to make sure his father, a Salt Lake City pediatrician, spent the rest of his life behind bars. He said his father's portrayal of himself as the victim was despicable and has profoundly compounded the grief he and his three siblings are feeling. "He's convinced himself of an alternate reality," Pelle Wall said outside court in Salt Lake City. "It's super disrespectful to true victims. I can't reconcile it." John Wall, 51, spoke before the packed courtroom saying emphatically "I did not kill Uta." He vowed to appeal the conviction. He lamented that his four children have lost their mother and father, and said he hopes they know he loves them unconditionally. "I can no longer assist them and support them in achieving their hopes and dreams. Nor can I comfort them in their times of need," said Wall, wearing a blue prison jumpsuit. "I'm left with only my memories." Pelle Wall, the only sibling in court, said he wasn't buying his father's speech. He said. "I don't know how he could have committed such a crime with any of his children in mind." The sentencing came after Blanch denied motions from John Wall's attorney to overturn the conviction on evidentiary issues. Blanch said he took note of Wall claiming his innocence but said the jury had found a "chilling and despicable crime." A jury convicted Wall in March after hearing a largely circumstantial case in which prosecutors said he attacked von Schwedler with a knife, gave her the anti-anxiety drug Xanax and drowned her in her bathtub. Defense attorneys countered that the theory was unbelievable, and it was more likely that von Schwedler killed herself. On Wednesday, attorney G. Fred Metos said prosecutors relied on a pyramid of inferences and multiple pieces of circumstantial evidence to make their case against Wall. In the lead-up to sentencing, Wall, his siblings and parents sent Blanch letters defending his character. Wall said people around him misinterpreted his confused state as guilt when he was actually dealing with grief and psychological trauma from police interrogation. His sister, Wendy Wall, said the man depicted during the trial bears little resemblance to the brother she knows. She said he was a loving, doting father who wasn't violent. She was in court along with other family but left without making comment. Pelle Wall remembered his mother, who died at 49, as a highly respected researcher who was driven and self-confident but also colorful, playful and goofy. He said he and his siblings still find themselves leaning on the lessons she taught them and miss her dearly. He said he's convinced of his father's guilt because he knows him well, and observed his interactions with his mother during a messy divorce and custody battle. Pelle Wall told reporters that he's also seen and heard all the evidence against his father gathered by authorities. "It all comes together and it all points to the same thing," Pelle Wall said. "That is that he's guilty."