Paris attack: 1 police officer killed

Paris attack: 1 police officer killed, 2 seriously injured in shooting on Champs-Élysées; ISIS claims responsibility
Officials: Paris attacker previously flagged as extremist.A police officer was killed and two others were seriously injured when a gunman opened fire late Thursday on the famed Champs-Élysées in Paris before he was shot dead, officials said. The Islamic State group quickly claimed responsibility for the attack.