Wednesday, in Southern California, a muslim couple stormed into a holiday office party, which mowed down 14 people before they had died hours later in a shootout with the citys police.

President Obama and local and federal authorities continued Thursday to resist calling the carnage at a San Bernardino social services facility terrorism, even as evidence mounted that the pair, who wore tactical gear and moved with grim precision, may have been armed to the teeth and hellbent on slaughtering innocent Americans. More than 5,000 rounds of ammunition were later found in their home, which sources described as “an IED factory” packed with explosives and bomb-making equipment.

“At this stage, we do not yet know why this terrible event occurred,” said Obama in an address from the White House, “We’ll get to the bottom of this and be vigilant getting the facts before we issue decisive judgments on how this occurred.”

Syed Rizwan Farook and Tashfeen Malik burst into the facility Wednesday morning and sprayed what is believed to be 75 rounds at Farook’s own terrified colleagues in a conference room where his employer, the county health department, was hosting a holiday party Farook had angrily bolted only moments earlier. The pair escaped in an SUV after their attack on him,  only to appear once again three hours later and less than 2 miles away in a gun battle on the city’s main drag.

“They came prepared to do what they did, as if they were on a mission,” said San Bernardino Police Chief Jarrod Burguan.

Farook, 28, who authorities said had worked as a $51,000-per-year restaurant inspector at the San Bernardino County Department of Public Health for five years, was described by co-workers as a “devout” Muslim, who lived with his wife, child and grandmother in a home in nearby Redlands.

At an afternoon news conference, Attorney General Loretta Lynch said the FBI had taken the reins of the investigation, and a bureau spokesman said a focus of the probe is digital evidence collected from their homes, including hard drives, thumb drives and cell phones. While those could be part of a terror investigation, and FBI spokesman said it was too soon to ascribe religion as a motive.

“It is a possibility, but we don’t know that,” said Assistant Regional FBI Director David Bowdich. “It’s possible it goes down that road. It’s possible it does not.”

 

The guns found on the suspects, two rifles and two handguns, were purchased legally, according to Meredith Davis, a spokeswoman for the Bureau of Alcohol, Tobacco, Firearms and Explosives. Burguan said Thursday Farook had purchased the handguns, but he did not say who had bought the rifles.

Estimated at about three hours after the shooting, with police looking for an SUV, officers staking out the Redlands home after being tipped off by a colleague disturbed by Farook’s exit from the party and saw a vehicle matching that description. Word that police were hot on their trail came even as emergency responders were treating the wounded on the scene, and sparked a flurry of law enforcement racing to the scene just blocks away. The gunfight, caught on cellphone video by a bystander, was a furious exchange in which 23 officers fired a total of 380 rounds at the suspects, according to Burguan.

“”Clearly they were equipped and could have done an other attack,” Barguan said. “Luckily we stopped them before that.”