As authorities identified the deceased and details about Farook's life began to take shape, the question of what motivated the slaughter remained unanswered.

The FBI was investigating the shootings as a potential act of terrorism but reached no firm conclusions Thursday, said a U.S. official briefed on the probe. Separately, a U.S. intelligence official said Farook had been in contact with known Islamic extremists on social media. Both officials spoke on condition of anonymity because they were not authorized to discuss the investigation publicly.

At the same time, law enforcement officials from local police to Attorney General Loretta Lynch cautioned it could have been work-related rage. Or a twisted hybrid of religion and personal vendetta.

Farook had no criminal record and was not under scrutiny by local or federal law enforcement before the attacks.

Authorities say that the couple sprayed as many as 75 rounds into the room before fleeing. They died four hours later and two miles away during a furious gunbattle with police.
The pair had more than 1,600 bullets when they were killed.

Police said they also had 12 pipe bombs, tools to make more explosives, and more than 3,000 rounds of ammunition at home.

Eoin Treacy's view

Regardless of one’s motivation it is a very strange situation indeed when a person concludes it is OK to spray bullets at one’s co-workers or to even begin to build a pipe bomb for that matter. Inspired by workplace shootings, ISIS or otherwise Syed Farook’s trip to Saudi Arabia in 2014 appears to have been life changing. It’s a PR success for jihadis who may or may not have had a part in it and a disaster for peace loving people and especially the families of victims to whom our hearts and good wishes go out. 

By all accounts the 1980 and 1990s were a difficult time to be Irish in London as the IRA escalated their bombing campaign. Anti-Irish sentiment might have been distasteful but it was certainly understandable in such circumstances. The clearest route one has to living in a harmonious society is to distance oneself from anyone who supports terrorism either culturally, politically or religiously. This is even more important when civilians are increasingly the targets of terrorist organisations. Muslim leaders need to make repeated, loud and clear statements that they disavow people fomenting such acts and take substantive steps to isolate them. 

Terrorists usually do much more damage to their own populations than those they are seeking to terrorise. ISIS’ actions in Syria and Iraq offer ample examples of that. They believe their strength rests in the misery of their populations and unfortunately there is an element of true in this. The worse the situation gets economically the greater the potential for new fighters to be recruited. It really is the responsibility of those in their own community and their global diaspora to disavow any and all support for such people. 

Military campaigns are necessary to control the symptoms of terrorism but they do little to tackle the cause. It is no coincidence that civil unrest has flared up over the last few years as oil prices have fallen. This illustrates how fragile Middle Eastern regimes are because of their failure to implement improving standards of governance and economic growth not dependent on government handouts.  
Global mobility means this problem is only going to intensify without some serious commitment on a coordinated basis to address it.