Hundreds of mourners gathered for a candlelight vigil on 7 December to remember the victims of the shooting in San Bernardino, California on 2 December. Syed Rizwan Farook, 28, and his wife, Tashfeen Malik, 29, killed 14 people in a mass shooting. The couple died hours later in a shootout with police.

Investigators believe the married couple had been radicalised "for quite some time," but no clues pointing to an international plot have yet emerged, the FBI said on 7 December. Authorities also have evidence that the couple engaged in firearms target practice near their Southern California home within days of the deadly shooting rampage, according to the FBI.

The latest disclosures in the FBI-led investigation came as San Bernardino County employees began returning to work under tighter security. The FBI said last week that authorities are investigating the mass shooting as an "act of terrorism," noting that Malik, a Pakistani native who lived most of her life in Saudi Arabia, was believed to have pledged allegiance on Facebook to the leader of the militant group Islamic State (Isis).