A clear motive behind the attack, described by prosecutors as an act of “political extremism,” remains unclear.

The suspect accused of fatally shooting a Minnesota lawmaker and her husband in a gun rampage in June has been indicted on six federal charges, the state's attorney general has announced.

Beyond the murder charges, Boelter’s indictment includes two stalking counts over his alleged efforts to track down both the former state speaker and state Sen. John Hoffman (D), whom Boelter alleged...