An investigation into the poisoning death of a Wisconsin mother reveals a surprising twist when a letter points to a possible suspect. Detectives uncover disturbing incidents and harassment in her life, leading them to suspect foul play. New evidence and suspicious circumstances surround Julie Jensen's death, including conflicting theories and potential suspects. Mark, the husband, is interrogated but released due to lack of evidence. A shocking revelation is revealed by a surprise witness. Ed Klug testifies that Mark expressed hatred towards his wife and discussed ways to kill her.