California massacre differs from lone-wolf shootings

Two suspects died in gunfight with police; FBI considers possibility of terrorist attack

Wednesday's mass shooting at a Southern California center for the developmentally disabled came on the heels of other US massacres but differed from most in key ways, including the involvement of multiple people, including a woman, and an apparently well-planned escape route.

In the San Bernardino area near the site of the attack that killed 14, police said a man and a woman dressed in tactical gear died in a gunfight with police, as the FBI said the agency was considering the possibility that the shooting could be a terrorist attack.