A son took the stand in his mother 's murder trial Wednesday to testify against his father . Pelle Wall testified in a Salt Lake City , Utah courtroom and described how happy and energetic his mother , Uta von Schwedler , had been in the year before she died , a death that was initially thought to be a suicide but is now believed by authorities to be a carefully plotted out murder on the part of her ex-husband and Pelle 's father , John Wall . Pelle also described his father 's erratic behavior in the hours after his mother died , including a moment when he sat down on his son 's bed and said to the young man , then still a teenager , 'What if I killed her and I do n't remember ? ' Scroll down for video . Pelle Wall ( above ) took the stand in the murder trial of his mother , Uta von Schwedler , in a Salt Lake City , Utah courtroom on Wednesday . Pelle testified against his father John Wall ( above ) , who is accused of killing his ex-wife and staging it to look like a suicide . According to the Deseret News , John had a very tempestuous relationship with his ex , and Pelle testified he would often say negative things about the woman in front of their children , telling them 'Uta 's a bad parent ' or 'Uta 's making my life difficult . ' He said on the stand the two would often argue when it came to the children , and that the last time he saw the two together , John rolled up his car window and drove off with the couple 's four children in the middle of a conversation that the two were having in von Schwelder 's driveway . Uta Von Schwedler ( above ) was found in her bathtub on Sept. 27 , 2011 with multiple cuts to her body and a high level of Xanax in her system . The next morning Pelle said he father was nowhere to be found , and when he returned home from school that afternoon he said the man had a large cut above his eye . Von Schwedler was found in her bathtub later that day with multiple cuts to her body and a high level of Xanax in her system . That night , John woke his son up while he was sleeping and began displaying 'erratic behavior , ' saying 'Uta 's dead and they think I did it . ' He then asked his son , 'Am I a monster ? ' and 'What if I killed her and I do n't remember ? ' Pelle testified that his mother had never taken any prescription pills or antidepressants to his knowledge , remembering her as 'happy ' and 'energetic . ' He also said that while his father initially seemed sad following the death of his ex-wife , that soon turned 'more toward anger , hatred . ' He also noted that after his parents first divorced , while he was still in elementary school , the children spent most of their time with their father , but that had changed in the years leading up to his mother 's death , with custody split between the two parents , something that angered his father . The 21-year-old has long believed his father killed his mother , moving out of his home when he turned 18 and petitioning the court to remove his three younger siblings from his father 's care shortly after . John , a pediatrician , has pleaded not guilty to the charge of murder .
Pelle Wall took the stand in the murder trial of his mother , Uta von Schwedler , in a Salt Lake City , Utah courtroom on the middle of the night the day . Pelle testified against his father John Wall , who is accused of killing his ex-wife and staging it to look like a suicide . Von Schwedler was found in her bathtub on Sept. 27 , 2011 with multiple cuts to her body and a high level of Xanax in her system . Pelle said his mother never showed any signs of depression or took any medication to his knowledge . He also testified to his father 's erratic behavior after the death of his mother , saying he woke him up in Wednesday she died . 'What if I killed her and I do n't remember ? ' Pelle says his father asked .