San Bernardino County employees began returning to work under tighter security on Monday, five days after a co-worker and his wife killed 14 of their colleagues at a holiday party.
Crisis counseling teams were reaching out to families of those killed and wounded on Dec. 2 in the fusillade from U.S.-born Syed Rizwan Farook, 28, and his Pakistani wife, Tashfeen Malik, 29. The couple died hours later in a shootout with police.
Most San Bernardino County workers returned to work on Monday for the first time since the massacre that President Barack Obama has called an act of terrorism, county officials said at a news conference.
Staff from the county's environmental health department, where Farook worked as an inspector, were expected to return to work Dec. 14.
Inside the San Bernardino suspects' home:
San Bernardino County Supervisor Janice Rutherford said the best way to honour the shooting victims was to return to normal operations.
"We can't be afraid," she said at the news conference.
Under the tightened security protocols at county buildings, some security guards who had previously been allowed only to observe and report incidents are now authorized to carry firearms and "engage and detain" assailants, James Ramos, chairman of the San Bernardino County Board of Supervisors, said.
The Federal Bureau of Investigation continued to seek a motive for the attack by Farook and Malik. Agents believe the couple had been planning more violence because of their cache of ammunition and pipe bombs.
Social reactions to journalists at San Bernardino suspects' apartment:
Investigators also are trying to determine if Malik was responsible for taking the couple's Muslim faith to the point of radicalisation.
The Italian newspaper La Stampa reported during the weekend that Farook's father said in an interview that his son was obsessed with Israel and had expressed support for Islamic State. A family spokesman later said the 67-year-old father denied making the comments.
Trauma doctors from Arrowhead Regional Medical Center in Colton, California, joined the news conference and talked about their experience.
"None of the 14 who perished had a chance," said Dr. Dev Gnanadev, a member of the 50-physician medical team that responded to the active shooter alert.
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San Bernardino shooting victims:
Hospital personnel scrambled to be sure there were enough ventilators, blood supply and other life-saving necessities as rumours swirled about the number of dead and wounded, Gnanadev said.
Dr. Michael Neeki, an emergency room physician, recalled patrolling the shooting area in an armoured vehicle with law enforcement, joining a SWAT team on a room-to-room search of an adjacent building, and being called to the scene where the shooters died in a gunbattle with police a few hours after the initial assault.
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