Navy Yard shooting in Washington, D.C. (21 images)

D.C. Metropolitan Police Officers work the crime scene at the Naval Yard in Washington, D.C. on September 16, 2013. Earlier this morning a gunman opened fire inside the Naval complex killing at least 12. UPI/Kevin Dietcsh

A D.C. Metropolitan Police Officers stands outside of the crime scene at the Naval Yard in Washington, D.C. on September 16, 2013. Earlier this morning a gunman opened fire inside the Naval complex killing at least 12. UPI/Kevin Dietsch

Police cars are seen in front of Nationals Park after tonight's Nationals game against the Atlanta Braves was postponed in the wake of the Washington Naval Yard shootings, in Washington, D.C. September 16, 2013. Earlier this morning alleged gunman Aaron Alexis opened fire at the Naval Yard killing at least 12 people and wounding 3. UPI/Kevin Dietsch

Police cars are seen in front of Nationals Park after tonight's Nationals game against the Atlanta Braves was postponed in the wake of the Washington Naval Yard shootings, in Washington, D.C. September 16, 2013. Earlier this morning alleged gunman Aaron Alexis opened fire at the Naval Yard killing at least 12 people and wounding 3. UPI/Kevin Dietsch