Accused Minnesota assassin Vance Boelter's alleged plan to kill more politicians on his target list was foiled by a police sergeant's proactive hunch.

Minnesota authorities arrested Vance Boelter, the suspect in the assassination of Democratic state Rep. Melissa Hortman and her husband and the failed assassination attempt of Democratic state Sen. John Hoffman and his wife, on Sunday afternoon after a daylong manhunt.

Vance Boelter is accused of posing as a police officer and fatally shooting former Democratic House Speaker Melissa Hortman and her husband, Mark, in their home early Saturday in the northern Minneapolis suburbs.