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.

Boelter, 57, was arrested at about 9 p.m. June 15. He is accused of shooting the two Democratic state legislators and their spouses in the early morning hours of June 14. The Minnesota State Patrol took him into custody in rural Sibley County, roughly 50 miles southwest of Minneapolis.