How the Nova Scotia mass shooter acquired guns in Maine

The inquiry into the deadliest mass shooting in Canada's history continues this week. Two years ago, a gunman dressed as an RCMP officer burned down houses and killed 22 people in Nova Scotia. CBC reporter Elizabeth McMillan explains how tracing the story of how the Portapique gunman got his weapons brought her to Houlton, Maine. And retired U.S. federal prosecutor Margaret Groban talks about how Maine is considered a source state for guns.