People gather for Friday prayers at the Dar Al Uloom Al Islamiyah-Amer mosque where shooting suspect Syed Rizwan Farook was seen two to three times a week at lunch time, in Bernardino, California December 4, 2015. Authorities are investigating the San Bernardino, California, shooting as an "act of terrorism", Federal Bureau of Investigation assistant director David Bowdich said at a news conference on Friday. REUTERS/Mike Blake