Police know that by early morning Saturday, Boelter had met a man at a Minneapolis bus stop who agreed to sell him an e-bike and a Buick sedan.

When the gunman in the shootings of two Minnesota lawmakers approached their homes early on Saturday morning, he was armed with not just a handgun but also a wealth of other gear: a black tactical vest, a badge, a flashlight, a Taser. He arrived in a black S.U.V. with flashing police lights.