US media outlets have also reported that either one or both of the pair travelled to Saudi Arabia, and that they may have had connections to individuals who had extreme Islamist views. Searching for answers near and far: an FBI agent at a car being investigated by police. Credit:AP The New York Times reported that the FBI had evidence Farook was in contact with extremists in the US and abroad, including at least one person in the US who had been investigated for suspected terrorism in recent years. "There was obviously a mission here," Bowditch said. "If you look at the amount of obvious pre-planning, the amount of weapons and ammunition." Mr Bowditch also flagged the possibility that the two shooters, who had amassed a large arsenal of weapons, ammunition and improvised explosives, were planning a larger-scale attack but had acted prematurely for unknown reasons.

"We don't know if this was the intended target or something triggered him to do this immediately," Mr Bowditch said. "It will take time to get that answer." FBI agents search outside a home in connection to the shootings in San Bernardino. Credit:AP Queried about the pair's international travel, Mr Bowditch said the bureau was "still working through that." He confirmed the pair returned to the US from Pakistan in 2014. At the time Farook was engaged to Malik, which allowed her to obtain a K1 visa. Syed Rizwan Farook, one of the San Bernardino shooters.

The pair subsequently married, she obtained permanent residency and they had a child. San Bernadino police chief Jarrod Burguan said his department had not ruled out the possibility that a larger attack, or an attack against a different target, had been planned, but that events had prompted the shooters to act. FBI agents investigate a car near a home in connection to the shootings in San Bernardino, California. Credit:AP "Clearly they were equipped and could have continued another attack," Burguan said. "We intercepted them before that happened obviously." One of the key indicators in the case for both law enforcement agencies is the huge cache of weapons and explosives the two shooters had amassed.

When stopped by police, the two shooters had "on their person and in the vehicle immediately available to them" roughly 1400 .223 caliber rounds, 200 .9mm rounds, two 223 assault rifles and two 9mm pistols. At another location, a home in nearby Redlands, police found another 2000 .9mm rounds, over 2500 .223 rounds and several hundred long rifle rounds. Police also found an improvised explosive composed of what seemed to be three pipe bombs at the site of the shooting, and another 12 pipe bomb-type devices in the home in Redlands. Police chief Burguan also confirmed the two shooters were dressed in black tactical gear; they were not, he pointed out, wearing bulletproof vests, as some media outlets had reported. Burguan said they had "tactical style" vests that held equipment and ammunition.