Timeline: Federal Employees Under Attack

Monday’s shooting at the Washington Navy Yard serves as a sad reminder that federal employees -- even civilians in seemingly secure facilities -- are too often targets of unexpected violence.

The latest tragedy, which was the “single worst loss of life in the District since an airliner plunged into the Potomac River in 1982, killing 78,” according to a report in The Washington Post , killed 12 civilian and contractor employees, in addition to gunman Aaron Alexis, himself a subcontractor for Hewlett-Packard working on a project to upgrade the Navy Marine Corps Intranet. As investigators attempt to piece together Alexis’ motive and how the troubled former Navy reservist gained a security clearance and access to the facility, we look back at some of the other attacks that have claimed the lives of government workers over the past two decades.