The death penalty hearing for admitted killer James McVay began Wednesday morning at the Minnehaha County courthouse.
McVay has pleaded guilty but mentally ill for stabbing 75-year-old Maybelle Schein to death in July 2011, as part of a plot to assassinate the president.
Prosecutors began Wednesday by telling the jury that they will prove McVay's crime was so vile that he deserves the death penalty.
But McVay's defense attorneys said McVay has a mental illness and was under the influence of drugs and alcohol at the time of the crime, which caused him to hallucinate and see 'spiritual entities' that told him to start killing.
Schein's niece, Dianna Stelling, was the first witness called by prosecutors. She said Schein was 'like a mother figure' to her and when she stopped by her home on July 2, 2011, she found her aunt dead in her bed.
"She was in a pile of her own blood," Stelling testified as she wept on the stand.
A jury of ten men and five women will hear the case and decide if McVay should be executed for the crime.