FBI Director James Comey says the two San Bernardino shooters were radicalized at least two years ago and had discussed jihad and martyrdom as early as 2013.
Comey told the Senate Judiciary Committee on Wednesday that Syed Rizwan Farook and his wife, Tashfeen Malik, were radicalized even before they met online.
The couple wed last year.
Comey also said the couple was inspired by foreign terror organizations and described them as "homegrown violent extremists."
He said the investigation is continuing.