How ballot drop boxes work and how officials keep them secure

Fires at two ballot drop boxes in the Portland, Oregon, area this week as well as a similar fire earlier this month have raised questions about the role of drop boxes in the upcoming election.

​ Fires at two ballot drop boxes in the Portland, Oregon, area this week as well as a similar fire earlier this month have raised questions about the role of drop boxes in the upcoming election. Read More Breaking News, Latest News and Videos | CNN