BAGHDAD, Iraq, June 8 — Al Qaeda's leader in Iraq, Abu Musab al-Zarqawi, was killed in an American air strike on an isolated safe house north of Baghdad at 6.15 p.m. local time on Wednesday, top United States and Iraqi officials said today. At a joint news conference with Iraq's prime minister, Nuri Kamal al-Maliki, the top American military commander in Iraq, Gen. George W. Casey Jr., said Zarqawi's body had been positively identified by fingerprints, "facial recognition" and "known scars." He said seven of Zarqawi's associates had also been killed in the strike. The announcement of Zarqawi's death, shortly...