A convicted killer put forward a unique defense while on trial for the murder of her estranged husband’s new girlfriend. Michelle Boat of Iowa blamed stress spurred by the COVID-19 pandemic for making her snap. Last March, Boat’s husband of 20 years left her and moved in with another woman, Tracy Mondabough. Boat left a threatening warning on her husband’s phone. Prosecutors say last May, Boat followed Mondabough home from an outing with her husband, got out of her car and stabbed her to death.