Charleston shooting anniversary: More work remains to end extremist violence

  A year ago last week, a young white supremacist gunned down nine black parishioners at a historic church in Charleston, South Carolina, marking the violent start to a lethal year of extremist violence in the United States.

  In San Bernardino, California, in the coming months, Islamist radicals would kill 14 people.

  In Colorado Springs, Colorado, an anti-abortion extremist would shoot three people to death at a Planned Parenthood clinic.