A law enforcement officer stands guard at the police line near a home being investigated by police. Fourteen people were killed when suspects opened fired at the Inland Regional Center in San Bernardino. (Marcus Yam / Los Angeles Times)
Richard A. Serrano, Paloma Esquivel and Richard Winton
December 2, 2015
Dressed in black masks and tactical gear, armed with long guns and pistols, they entered a holiday party for county health workers in San Bernardino as it was in full swing. Before they fled, they had killed 14 people and wounded 17 others.