Earlier Wednesday, two senior U.S. counterterrorism officials told NBC News that one of the suspects in the attack had been killed and that two others were in custody. However, the officials later said the information that was the basis of that account could not be confirmed. (…)

A source familiar with the investigation told NBC News on Wednesday night that two officers who had been assigned to protect editor and cartoonist Stephane Charbonnier for the past several years came down from an upper floor and intercepted the gunmen. Both officers were shot, however, and one died at the scene.