Investigators are still trying to determine a motive for the mass shooting in San Bernardino, California.

FOX's Jeff Monosso reports:

U.S. intelligence sources tell us that Syed Farook was in contact with radical extremist groups that were on the FBI's radar. And that in addition to jihadist materials found inside the couple's rental home described as a bomb-making factory.

We're also being told that there's also evidence that show Farook and wife Tashfeen Malik had possible plans for a separate target before police neutralized the couple in a shootout.

(Burguan) "Of the fourteen people that are deceased, and their identities have been released now, twelve of those individuals were county employees... County of San Bernardino."

Police Chief Jared Burguan. 

Eighteen of the 21 hurt also county employees -- ten of whom are still hospitalized.

In San Bernardino, California, Jeff Monosso, FOX News.