Vance Boelter, the Minnesota man accused of impersonating a law enforcement officer and fatally shooting the state's former House speaker in what authorities have described as a politically motivated assassination, pleaded guilty Thursday. Boelter, 58, dressed in an orange sweatsuit, responded "yes" when the judge asked whether he carried out the crimes, which killed Democratic state Rep. Melissa Hortman and her husband, Mark, and injured Democratic state Sen. John Hoffman and his wife, Yvette Hoffman.