A forensic pathologist testified the antidepressant drug Nortriptyline was found at toxic levels in the wife of the Oswego man accused of killing her and their three children.
However, Larry Blum said Thursday the level readings can go up threefold after death. He also noted the Food and Drug Administration has said the antidepressant and an anti-seizure medicine found in her body could cause suicidal thoughts.
Blum's testimony came in the Will County trial of Christopher Vaughn, who prosecutors say killed his wife and children in June 2007 so he could move to Canada.
Vaughn's attorneys say his wife committed the killings because she was distraught over marriage troubles.
Blum conceded to Vaughn's defense attorney he couldn't rule out suicide in the case of Kimberly Vaughn.