By: Mitch Smith, Lazaro Gamio, Emily Cochrane, Michael Wines, Katie Robertson, Kaleigh Rogers, June Kim, Tracey Tully, Eduardo Medina, Jack Healy, Delilah Brumer, Aishvarya Kavi, Zolan Kanno-Youngs, Erin Nolan, Julie Bosman, Grace Ashford, Charles Homans, Nate Cohn, Carl Hulse, Jonathan Weisman, Katie Glueck, Jenn Ackerman, Patricia Mazzei
The threat, one of at least six received in Arizona today, is likely to slow ballot counting in La Paz County.