Officers on Capitol Hill look at a car following Thursday's shooting, which left Miriam Carey, 34, dead. "We're still very confused as a family why she's not still alive," Carey's sister says. Charles Dharapak/AP hide caption

itoggle caption Charles Dharapak/AP

An officer stands just outside police tape Thursday as authorities investigate a car chase that began at the White House and ended near the Capitol. Lv Mingxiang /Xinhua/Landov hide caption

itoggle caption Lv Mingxiang /Xinhua/Landov