A gunman posing as a police officer killed a senior Democratic state assemblywoman and her husband on Saturday in an apparent "politically motivated assassination," and wounded a second lawmaker and his spouse,

Vance Luther Boelter, 57, was arrested on Sunday for allegedly killing a Minnesota Democratic state lawmaker and her husband while posing as a police officer, Governor Tim Walz said.

Authorities say he also shot Sen. John Hoffman, a Democrat, and his wife, Yvette.