US officials now think the female assailant in the attack in San Bernardino pledged allegiance to the leader of the Islamic State group.
Investigative officials have told media outlets that they found a message posted up by Pakistani born Tashfeen Malik.
She acted alongside her husband Syed Rizwan Farook, using assault rifles to kill 14 of his work colleagues at a holiday party, injuring 21 others, before being shot dead after a police chase.
The FBI has so far declared no motive, but our Washington Correspondent Daniel Ryntjes says evidence is mounting that this was terrorist inspired.
IN: These individuals...
OUT: ...concocted themselves.
DUR: 43"